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  • CN 31-1633/O6
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Schiff-Base Type Polymeric Electronic Transport Material Based-on S-Heterocycles Fused Naphthalene Diimides
LI Jiangao, LI Jing, GAO Xike
 doi: 10.14133/j.cnki.1008-9357.20190523001
[Abstract](2194) [FullText HTML](265) [PDF 2785KB](11)
A library of π-conjugated systems has been developed through conventional tools of coupling (e.g. Suzuki coupling, Stille coupling) and has been used for the fabrication of organic optoelectronic devices. Herein, we outline a facile, atom-efficient and environmentally benign pathway, with water as the only by-product, for the synthesis of conjugated Schiff-based copolymers based on sulfur-heterocycle fused naphthalene diimides (NDIs) and aromatic diamines. These copolymers showed broad absorption spectra in the ultraviolet-visible (UV-vis) region and low-lying LUMO levels at about −4.07~−4.19 eV. The relationship between the chemical structure and performance, including the optical properties, electrochemical properties, thermal stability, morphologies and the field-effect performance in transistors, was fully studied using these polymers as active layer. Compared with P1 and P2, P3 exhibits an absorption peak at 754 nm, with red shifts of 76 and 75 nm, respectively. An electron mobility of up to 2.47×10−3 cm2 V−1s−1 can be achieved for P3-based transistors after performing a thermal annealing process at 300 ℃. Our work demonstrate that the incorporation of rigid structure units into polymer conjugated skeleton can effectively tune its spectral absorption, energy level structure as well as the film morphology, thus improving the device performance.
Advances in Construction Strategies of Low-Complication Medical Coatings
SHI Hengchong, CHE Chaoyue, LUAN Shifang, YIN Jinghua
 doi: 10.14133/j.cnki.1008-9357.20190514001
[Abstract](2130) [FullText HTML](262) [PDF 1998KB](10)
The functionality of medical materials is mainly exhibited by the contact between the surface of the medical material and the biological environment. It is necessary to functionalize the surface of the medical material. Otherwise, complications such as bacteria-induced infection and blood clot-induced thrombosis may occur during the implantation/intervention process. This leads to shortened service life and application failure. Based on the above problems, controlling structural composition, constructing functional surfaces, achieving low complications and biocompatibility on the surface of materials have always been important scientific problems that need to be solved in this field. At present, the construction methods of low-complication medical coating mainly include surface chemical graft modification, monolayer self-assembly, layer by layer assembly, dopamine coating, etc. Combined with the research group's low-complication medical polymer materials and medical treatment in recent years, the research results of medical coatings of instruments have briefly introduced the research progress of the surface construction of medical coatings at home and abroad.
Preparation and Properties of Dual Dynamic Covalent Bond Crosslinked Hydrogels
TONG Yanping, XIAO Yan
 doi: 10.14133/j.cnki.1008-9357.20190430002
[Abstract](2120) [FullText HTML](249) [PDF 1105KB](7)
Poly(sarcosine-co-glutamate hydrazide) (P(Sar-co-GH)) with good water solubility and hydrazide group and oxidized sodium alginate (OSA) with aldehyde group were designed and prepared. Under mild conditions, hydrogels composed of P(Sar-co-GH), OSA and carboxymethyl chitosan (CMC) could be prepared based on acylhydrazone bonds formed between P(Sar-co-GH) and OSA and imine bonds formed between CMC and OSA. The structure and mechanical properties of the hydrogels were characterized by FT-IR and rotational rheometer. The mechanical properties of hydrogels can be adjusted from 840 Pa to 5 690 Pa by changing the content of P(Sar-co-GH) and CMC. The double dynamic chemical bond hydrogel can be injected by the 23 G needle and also exhibit the self-healing behavior within 12 h. Moreover, the hydrogels can undergo repeated gel-sol transition under the regulation of triethylamine(TEA) and hydrochloric acid(HCl). In vitro cytotoxicity and cell culture experiments demonstrate that copolymer and hydrogel extract are nontoxic to mouse embryonic cells(NIH/3T3) and can support NIH/3T3 growth and proliferation. Overall, a new hydrogel based on polypeptide and polysaccharide is developed by dual dynamic covalent bond, which endows the material with injectability, self-healing properties and pH responsiveness and has great potential in biomedical field.
The Preparation and Characterization of Hyperbranched Poly(amino-ester) with Poly(ethylene glycol)
GAO Xiang, LUO Jing, QIAN Jiayi, LIANG Xue, ZHANG Yifan, LI Xiaojie, CHEN Mingqing
 doi: 10.14133/j.cnki.1008-9357.20190225002
[Abstract](3016) [FullText HTML](664) [PDF 7253KB](8)
Hyperbranched poly(amino ester)s with the surface containing acrylate bonds, backbone containing polyethylene glycol (PEG), and interior containing tertiary amines have been synthesized via an one-step route associated with the michael addition polymerization of trifunctional amine, 1-amino-2-(ethylamino)ethane (B'B2-type monomer), and a double molar diacrylate, polyethylene glycol diacrylate (A2-type monomer). The hyperbranched poly(amino ester) was modified with imidazole by michael addition reaction of acrylate in hyperbranched poly(amino ester)s and amine in imidazole. The polymerization kinetics of hyperbranched poly(amino ester) was studied by 1H-NMR. The chemical structures of these hyperbranched polymers were confirmed by 1H-NMR, GPC and FT-IR spectra. The results showed that the molecular weight of the hyperbranched poly(amino ester) modified with imidazole was 1.42×103 kg/mol, and the polydispersity index(PDI) was 1.05. The water solubility and pH responsiveness of the hyperbranched polymers were investigated by Zeta potential analyzer. The results demonstrated that the hyperbranched polymers showed excellent water solubility due to the presence of polyethylene glycol(PEG) backbone. Additionally, the hyperbranched poly(amino-ester) modified with imidazole has numerous tertiary amines which make the polymer carry more charges than the hyperbranched poly(amino-ester), therefore offering it with more sensitive pH responsiveness.
Sodium Polyacrylate/Sodium Sulfate Decahydrate Phase Change composites
LU Tiemei, ZHU Zixuan, HU Hu, YANG Rui
 doi: 10.14133/j.cnki.1008-9357.20190301002
[Abstract](1273) [FullText HTML](136) [PDF 1418KB](4)
Na2SO4·10H2O is a promising phase change material for energy saving buildings. In order to suppress the phase segregation and diminish the super-cooling degree of Na2SO4·10H2O, PAA/Na2SO4·10H2O phase change composites were prepared in this work through absorbing the molten sodium sulfate decahydrate (Na2SO4·10H2O) into the sodium polyacrylate (PAA) matrix. The polymerization condition of PAA was optimized to obtain maximal absorption of Na2SO4·10H2O. The optimal condition was: N, N-methylenebisacrylamide (Bis, as crosslinking agent) content of 0.02 wt%, ammonium persulfate (APS, as initiator) content of 0.1 wt%, neutralization degree of 75%, acrylic acid (AA, as monomer) content of 30%, polymerization temperature at 70°C, and reaction time of 3 h. The morphology and microstructure, phase changing behavior, thermal stability and thermal cycling stability of the phase change composites were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), polarized optical microscope (POM) and scanning electron microscope (SEM). The results showed that the absorption amount of Na2SO4·10H2O in the PAA matrix can be as much as 93%. The three-dimensional network structure effectively inhibited the phase segregation of Na2SO4·10H2O and formed stable phase change composites. Moreover, the phase change composites had high latent heat, exhibiting good thermal stability and cycling stability, and the phase change temperature and enthalpy maintained nearly unchanged after 45 heating-cooling cycles. The supercooling degree of PAA/ Na2SO4·10H2O was further decreased by adding borax. With 5 wt% borax, the supercooling degree of the phase change composites can be decreased to 1.0 °C. Furthermore, no leakage was observed during the heating procedure even when Na2SO4·10H2O was melt.
Advances in Organic Second Nonlinear Optical Polymers
HUO Fuyang, CHEN Zhuo, BO Shuhui
 doi: 10.14133/j.cnki.1008-9357.20190507001
[Abstract](2831) [FullText HTML](514) [PDF 2118KB](19)
Nonlinear optical materials play very important role in some advanced technology areas, such as laser, optical communication, optical processing, high-frequency electro-optical devices and terahertz areas. Compared with the traditional inorganic materials, organic second-order nonlinear optical materials have the advantages of high electro-optic coefficient, fast response as well as easy processing. In the past 20 years, the research focusing on organic nonlinear optical materials and devices was a hot area, especially the high-frequency electro-optical modulators have received extensive attention. This review systematically describes the research progress in recent years and future development directions in the field of organic second-order nonlinear optical materials. Research results have shown that the electro-optic properties and orientation stability of materials can be effectively turned through molecular design strategies and chemical synthesis, structural relationship between chromophores and polymers, and doping techniques. However, there are still many challenges in developing organic nonlinear optical materials with excellent properties to meet the requirements of practical applications.
Preparation of Janus Hybrid Gold Nanoparticles Based on Asymmetric Star Polymers
LIU Ziqiang, ZHANG Guoying
 doi: 10.14133/j.cnki.1008-9357.20190819001
[Abstract](15) [FullText HTML](22) [PDF 1044KB](3)
A highly efficient and simple method for preparing Janus gold nanoparticles (AuNPs) with small size capable of self-assembling was developed. Firstly, the asymmetric star polymers ((LA)7-CD-(PNIPAM46)14) were fabricated based on β-cyclodextrin (β-CD) by combining atom transfer radical polymerization (ATRP) and click chemistry. The secondary hydroxyl groups on the wide cross section of β-CD molecule were modified to be ATRP initiator moieties, which then initiated the polymerization of N-isopropyl acrylamide (NIPAM) to form fourteen PNIPAM chains via ATRP. The primary hydroxyl groups on the narrow cross section of β-CD molecule were converted into azide groups and then coupled with 5-(1,2-dithiolan-3-yl)-N-(prop-2-ynyl) pentanamide molecules by click chemistry. The obtained asymmetric star polymers ((LA)7-CD-(PNIPAM46)14) were used to modify AuNPs that were formerly surface stabilized by n-butylthiol through the ligand exchange process. Due to the steric effect of (LA)7-CD-(PNIPAM46)14 macromolecules, Janus hybrid AuNPs, Au-CD-(PNIPAM46)14, with amphiphilic surface were prepared, which can self-assemble in water into micelle-like aggregates, i.e. supermicelles. The chemical and chain structures of asymmetric (LA)7-CD-(PNIPAM46)14 star polymers and the amphiphilic Janus hybrid Au3.1-CD-(PNIPAM46)14 nanoparticles were characterized by Nuclear Magnetic Resonance (NMR), Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS), Gel Permeation Chromatography (GPC) and Thermal Gravimetric Analysis (TGA). The morphology and structure of the prepared micelle-like self-assemblies were investigated by Transmission Electron Microscope (TEM).
Research Advance in Selective Permeable Materials of Skin Protection
ZHAO Yue, LI Lei, LI Heguo, WANG Xinbo, WANG Deyin, MEN Quanfu, WU Liang, ZHONG Jinyi
$v.latestStateEn  doi: 10.14133/j.cnki.1008-9357.20190628001
[Abstract](1790) [FullText HTML](242) [PDF 2013KB](3)
Chemical weapons were used to be applied on a large scale for the first time in World War I. In its continuous development, chemical weapons showed such characteristics as wide killing range, long killing time, multiple poisoning route and low manufacturing cost, and aroused the general attention of military scientists and even caused a major threat to national security and social stability. From traditional chemical weapons to non-traditional chemical threats such as secondary chemical disasters and chemical terror, chemical protective clothing have always been an important equipment to resist these chemical threats. After development of nearly a century, chemical protective clothing has formed a clothing series mainly composed of air impermeable and air permeable type. With the constant development of the threat situation towards stealth variation, it is urgent to make breakthroughs in the protection principle and new materials, so as to realize the comprehensive improvement of the broad-spectrum protection ability and physiological comfort of chemical protective clothing. Recently, a new type of chemical protective clothing called selective permeable type came into being and caused wide attention. This kind of protective clothing has excellent comprehensive performance, whose core is selective permeable material. This selective permeable material can make reliable barrier against chemical toxic agents and efficient transmission of water vapor. According to the difference types and mechanism of selective permeable materials, this paper reviews the materials based on the ion exchange membrane, carbon-based polymer composite material, metal organic frameworks (MOF) polymer composite materials, the polyoxometallates (POM) polymer composite materials, decontamination functional polymer, and introduces the protection, decontamination, moisture permeability and other properties.
Preparation and Properties of Collagen/Cellulose Nanocrystals Dressing
ZHOU Shuyu, XU Shuqin, LIANG Liyuan, CHEN Jinghua
 doi: 10.14133/j.cnki.1008-9357.20181225001
[Abstract](2636) [FullText HTML](538) [PDF 1564KB](10)
The composite films based on collagen (Col) reinforced by dialdehyde cellulose nanocrystals (DACs) were fabricated for wound dressing. Cellulose nanocrystals (CNCs) were obtained by acid hydrolysis. The surface of CNCs was treated by sodium periodate to produce DACs with different degrees of oxidation (DO = 8.6%—51.3%). The length and height of DACs were (208 ± 30) nm and (9 ± 3) nm, respectively. The Col/DACs-IBP multilayer films were prepared by alternately filtering DACs-Ibuprofen (IBP) solution and Col solution. The structure and property of the films were characterized by scanning electron microscopy, electronic universal testing machine, and UV-Vis spectrophotometer. The aldehyde groups of DACs reacted with the amino groups of Col, resulting in chemical cross-linking networks between the adjacent layers. Therefore, increasing DO of DACs and/or improving the dispersity of DACs and Col could enhance the covalent interactions between the adjacent layers, by which tight and uniform structure of films were formed. The Col/DACs-IBP multilayer films showed outstanding mechanical properties and light transmittance. The optimal tensile strength was 54.2 MPa, which was improved by 152.1%. The optimal light transmittance was up to 95.7%, which was improved by 13.5%. The water holding capacity of the films was reduced upon increasing DO of DACs. in vitro Drug release experiments suggested that the IBP loaded in films was slowly released up to 89.0% within 24 h. Furthermore, the films could obviously promote the adhesion and proliferation of cells within the test time.
Synthesis and Ultraviolet Resistance of Macromolecule Ultraviolet Absorbents
CAI Yi, GAO Fengxiang, ZHANG Yaming, ZHOU Qinghai, WANG Xianhong
 doi: 10.14133/j.cnki.1008-9357.20190824001
[Abstract](2175) [FullText HTML](278) [PDF 1102KB](11)
2-Hydroxy-4 (2,3-epoxypropoxy) benzophenone (HEB) was prepared by the reaction of 2,4-dihydroxybenzophenone (DBP) with epichlorohydrin. The structure of HEB was characterized by 1H-NMR, FT-IR, UV spectroscopy, respectively. Continuous feeding method of propylene oxide (PO) that could obviously increasing the apparent concentration of HEB was used to overcome the problem of low reactivity ratios of HEB during the terpolymerization of HEB with PO and CO2. Polymeric UV-absorbent PPCH with number-average molecular weight of 3.0×104, polydispersity index of 4.77 and HEB mol ratio of 0.9% was successfully synthesized. To show the advantage of anti-UV irradiation performance of this PPCH, PPC/DBP blends and PPC/PPCH blends with similar HBP (2-hydroxybenzophenone) mass fraction were prepared for 120 h of xenon-arc weathering. The apparent number-average molecular weight of PPC/DBP blends decreased by 36%, accompanied by tensile strength loss of 26.4%, while The apparent number-average molecular weight of PPC/PPCH blend decreased by only 13.4%, accompanied by insignificant tensile loss of 3.6%. The migration resistance of UV absorber in PPC/PPCH was confirmed, where PPC blend with the similar DBP content was used as a reference for hot water (50 ℃) extraction test for 120 h, few UV absorbers was extracted in PPCH providing stable UV absorption performances, while the PPC/DBP blend showed sharp drop in UV absorption upon the extraction of hot water. Therefore, the macromolecule-based of ultraviolet-absorbers are an effective way to solve the problems of external migration of ordinary small molecular UV absorbers.
Effect of Ethanol on the Interface of Carbon Fiber Reinforced Polymers Composites
YANG Futing, YANG Chongchong, LI Yinghao, ZHENG Zhen, WANG Xinling
 doi: 10.14133/j.cnki.1008-9357.20190225001
[Abstract](2479) [FullText HTML](422) [PDF 1932KB](5)
Carbon fiber reinforced polymer composites (CFRPs) have been widely used in the fields of astronautics and aviation due to their superior strength, modulus as well as the potential of being tailored for various applications. As a two-component material, the interface between a fiber and matrix is very important for the properties of CFRPs. Therefore, the interfacial characterization is of specific interest in understanding and tailoring the performance of CFRPs, in which microscopic characterization is a research hotspot. Atomic force microscope (AFM) is an effective tool for characterizing the topography and properties of different types of materials. However, employing AFM to characterize the interfaces in CFRPs is very rare. Solvents are often used to clean the composites, but the potential effects of solvents on the composites have not been fully understood. In order to study the evolution of interfacial structure of CFRPs under the effect of ethanol, a characterization method on the CFRPs interface involving the in situ observation of size of the resin and the fiber was proposed. The cross-section and laminate samples were prepared with carbon fibers and epoxy resin, and treated with ethanol. The morphology near the interface of the samples was measured by an environment control scanning probe microscopy (ECSPM) with in situ heating, and the interlaminar shear properties of the samples were analyzed by short beam shear tests. The results showed that the resin around the interface expanded after the ethanol treatment. During the heating process, the resin shrinkage and the fiber expansion of CFRPs treated with ethanol occurred remarkably. However, the interlaminar shear strength and the failure modes of CFRPs were not significantly affected by the ethanol treatment. In summary, short-term ethanol treatment may have a potential impact on the surface properties of CFRPs during its function, but not enough on its shear resistance.
Synthesis and Characterization of Self-Healing Elastomers Based on Coordination Bonds
BAI Zhiwei, ZHANG Zhibin, Zhang Yajuan, WANG Jikui
 doi: 10.14133/j.cnki.1008-9357.20190227002
[Abstract](2301) [FullText HTML](636) [PDF 1128KB](12)
Aminopropyl terminated polydimethylsiloxane (APT-PDMS) was synthesized by the ring-opening equilibrium reaction of octamethylcyclotetrasiloxane (D4) with using 1,3-Bis(3-aminopropyl)tetramethyldisiloxane as a blocking agent. The silicone elastomer (PDMS-DAP) was synthesized by forming a prepolymer of diisocyanate and APT-PDMS, followed by the addition of 2,6-Diaminopyridine (2,6-DAP) as a chain extender, Finally, a series of self-healing silicone elastomers (PDMS-DAP/M) were obtained through the formation of coordination bond between PDMS-DAP and iron ions. The structures of product were characterized by nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR) and Ultraviolet-visible spectrophotometer (UV-Vis spectroscopy). Water contact angle measurement and universal testing machine were used to characterize the surface properties and mechanical properties of the materials. The self-healing performance of PDMS-DAP/M were studied by laser confocal microscopy, and the mechanical properties of the healed samples were tested by universal testing machine. The results showed that the PDMS-DAP/M were successfully synthesized. The hydrophobicity of the material was less affected by the modification of PDMS, and the water contact angle was higher than 90°. It has good waterproof performance. The prepared PDMS-DAP/M have excellent mechanical properties and satisfactory self-healing ability. The effects of different ratio of pyridine group and iron ion contents on the elastomer properties were investigated in this study. With the increasement of iron ion, the tensile stress of PDMS-DAP/M was increased from 0.95 to 1.96 MPa due to the increase in the crosslinking density between the pyridine groups and iron ions. Meanwhile, the self-healing efficiency of PDMS-DAP-3 with the highest tensile stress can reach at 82 % for only 6 h. These results indicated that the self-healing silicone elastomer can be an ideal candidate for the self-healable flexible substrates which can be used in flexible electronics and other applications involving resources saving and environment protection. In addition, the self-healing efficiency of PDMS-DAP/M can be improved by increasing the temperature, by which the repairing time can be decreased.
A Copper Nanoparticles – Calcium Alginate Composite Bactericidal Film Prepared by Electrophoretic Deposition Technique
LEI Yü, QÜ Xue
$v.latestStateEn  doi: 10.14133/j.cnki.1008-9357.20190415002
[Abstract](2133) [FullText HTML](250) [PDF 1051KB](9)
In this work, by adjusting the copper nanoparticle composition in electrolyte, a series of new bactericidal alginate calcium-copper nanoparticle nanocomposite films, denoted by Ca2+-Alg-Cu were prepared by electrophoretic deposition with constant current mode and according to the content of copper nanoparticle amount in the final formed film denoted by Ca2+-Alg-Cu10, Ca2+-Alg-Cu20 o Ca2+-Alg-Cu50, respectively. By the usual experimental characterization techniques such as scanning electron microscopy (SEM), energy dispersive spectrometer (EPS) and Fourier-transformed infrared spectroscopy (FTIR) characterizations confirmed the existence of copper nanoparticles in the nanocomposite films (denoted by Ca2+-Alg-Cu, Ca2+-Alg-Cu = Ca2+-Alg-Cu10, Ca2+-Alg-Cu20 and Ca2+-Alg-Cu50). Three different common infectious bacteria including E. coli., S. aureus. and P. aeruginosa are taken as infectious pathogen models to explore the bactericidal property of Ca2+-Alg-Cu by plate counting method for 24 h. In addition, external animal skin cells such as mice L929 fibroblasts were incubated with Ca2+-Alg-Cu to assess the in vitro biocompatibility. The result shows that Ca2+-Alg-Cu can potently kill the three representative bacteria species by inducing cellular exterior membrane deformation and wrinkling, which is the inferred way of destruction in cellular structure. The potency of Ca2+-Alg-Cu depends on copper nanoparticle (Cu) content in electrolyte and it is more potent if there are linearly more copper nanoparticles as can be seen in the experimental result. If the content of Cu in electrolyte is lower than 0.4 mg/mL, the cellular viability is greater than 80%, which indicates a compatible arrangement of both the antimicrobial potency and tolerant to the animal skin extracted cells, here is mice, to achieve a balanced bactericidal property and in vitro biocompatibility can be realized.
Copolymerization of Ethylene Brassylate with Small Lactones Using a Mono(phosphinoamide) Rare-Earth Yttrium Complex
DONG Jinghan, YANG Ke, YU Hui, NIU Hui, LI Yang
 doi: 10.14133/j.cnki.1008-9357.20190130001
[Abstract](2257) [FullText HTML](341) [PDF 1043KB](9)
On the basis of a novel mono(phosphinoamide) rare-earth yttrium complex, (2,4,6-Me3C6H2NPPh2)Y(CH2C6H4NMe2-o)2, the copolymerizations of ethylene brassylate (EB) with δ-valerolactone (δ-VL) and ε-caprolactone (ε-CL) were realized, respectively. Copolymers with different compositions were synthesized through a one-pot ring-opening polymerization approach with a monomers/catalyst molar ratio of 200. Such an approach is featured by solvent-free and mild conditions (for 24 h at room temperature). The average sequence lengths and randomness characteristics of the copolymers were analyzed by nuclear magnetic resonance (NMR). Furthermore, the crystallization behaviors and thermal properties were investigated by differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD) and thermogravimetric analysis (TG). Results showed that the yields of the copolymers could reach 80%—90% when the reactions were conducted for 24 h; and the composition ratios in products were in good agreement with the feed ratios. The catalyst was efficient for the copolymerization, resulting in the copolyesters with high molecular weights (Mn > 3×104) and narrow molecular weight distributions. The number average length and randomness of copolymers indicated that the copolymers had a block structure and presented a deviation from the random distribution of sequences (R = 0.25—0.36). The resulting block copolymers were able to crystallize over the entire range of composition, and the existence of EB sequences and the block structure had a significant effect on the thermal stability of the copolymers.
Nano-Scale Ultrasound Contrast Agent Based on Hyperbranched Polyether
LI Jie, HUANG Ping, WANG Cong, YANG Shaoling, ZHOU Yongfeng
 doi: 10.14133/j.cnki.1008-9357.20190127001
[Abstract](2593) [FullText HTML](554) [PDF 1160KB](16)
Hyperbranched polyether HBPO-star-PEO (HSP, HBPO: hyperbranched poly(3-ethl-3-oxetanemthanol; PEO: polyethylenegluycol)) with different PEO arm lengths were synthesized by cationic ring-opening polymerization. A series of ultrasound contrast agents (UCA) were prepared using HSPs as shell materials and SF6 as inner gas, which are named as HSP-UCA. The size, micromorphology, SF6 concentration and in vitro/in vivo ultrasound imaging effect of HSPs-UCAs were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), gas chromatography-mass spectrometry (GC-MS), and ultrasound imaging instrument. The results showed that analogous to the effect of PEO arm length on the stability of the vesicles, the stability of UCA increased with the PEO arm length, resulting in an increase in its concentration. When the PEO arm length was increased to 10, high concentration of HSP10-UCA was obtained with a average size of 517.3 nm, the SF6 volume fraction of 9.12 ×10−3 and the in vitro ultrasound half-life of 3−5 min. in vivo Ultrasound test of HSP10-UCA in rabbit heart showed good ultrasound contrast effect. Before the injection of nano-scale HSP10-UCA, the ultrasound echo signal inside the heart was very low and the internal structure could not be observed by ultrasound imaging. However after intravenous injection of HSP10-UCA, the rabbit heart was quickly perfused, its internal structure was slowly appeared. The average ultrasound contrast durations of HSP10-UCA were 50−60 s. The above results indicate that the nano-scale HSP10-UCA is an excellent ultrasound contrast agent and its good ultrasound contrast effect will be beneficial to its future applications in the ultrasound imaging of tumor tissues.
Regulating the Shape Recovery Stress of Aligned Fibrous Mats with Shape Memory Capability
HUO Ying, WANG Xianliu, YI Bingcheng, SHEN Yanbing, ZHANG Yanzhong
 doi: 10.14133/j.cnki.1008-9357.20190105002
[Abstract](2046) [FullText HTML](381) [PDF 1321KB](15)
Shape memory polymers (SMPs) are smart polymeric materials that have the capability to return from a deformed state (temporary shape) to their original (permanent) shape in response to an external stimulus. Engineering those biodegradable SMPs into fibrous form will thus offer new functionalities to the fibrous implants (e.g., intelligent surgical sutures and tissue-engineered scaffolds) in the field of biomedicine. However, up to now very few has been done in terms of making use of the shape recovery force of SMPs. On the basis of an already established stable jet electrospinning approach, aligned composite fibers of PLLA/PHBV consisted of biodegradable poly(L-lactic acid) (PLLA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) were prepared in this study. Thereafter, shape memory effect of the electrospun aligned PLLA/PHBV fibers was evaluated. Based on the shape-programming principle of SMPs, the prepared aligned PLLA/PHBV fibers were stretched at high temperature and cooled down to fix the shape/strain, giving rise to the aligned fibers with different tensile strains for regulating the shape recovery stress. The morphology, tensile properties, molecular orientation and shape recovery of the programmed fibers were systematically characterized. The results show that the aligned PLLA/PHBV fibers possess good shape memory performance, and the shape fixing and shape recovery rates are (96.79 ± 0.64)% and (71.64 ± 8.87)%, respectively. Shape recovery stress of the aligned PLLA/PHBV fibers programmed at different tensile strains was measured from 0 (ε = 0) to (5.32 ± 0.32)MPa (ε =40%), (7.63 ± 0.26)MPa (ε =70%), and (9.24 ± 0.13) MPa (ε = 100%), confirming the feasibility of tuning shape recovery stress via controlling tensile strain of the aligned fibers. This study provides a basis for future investigations on the shape-recovery effect of shape-memory aligned fibers for the regulation of cell function in engineering structurally anisotropic tissues (such as tendons, ligaments, etc.).
WPU/MMT Nanocomposite Dispersion Based on Polyetheramine Modification
KONG Ziwen, SHAN Ning, FU Yang, SU Yi, ZHOU Zhongwu, DONG Weifu, ZHANG Shengwen
 doi: 10.14133/j.cnki.1008-9357.20181213001
[Abstract](2987) [FullText HTML](617) [PDF 953KB](5)
Polyetheramine modified montmorillonite (PEA-MMT) was prepared by inserting polyetheramine (PEA) into the montmorillonite layers through the way of ion exchange. The chemical structure of PEA-MMT was characterized by Fourier transform infrared spectroscopy (FT-IR). X-ray diffraction (XRD) analysis showed that the basal spacing of PEA-MMT was larger than that of unmodified MMT. The waterborne polyurethane (WPU)/polyetheramine modified montmorillonite (WPU/PEA-MMT) nanocomposite dispersions were prepared by incorporation of the functionalized montmorillonite during the emulsification process of the polyurethane prepolymer. The influence of the addition of PEA-MMT on the WPU properties including micromorphology, mechanical properties, water absorption and oxygen permeability were studied. Scanning electron microscopy (SEM) analysis confirmed that PEA-MMT was homogeneously dispersed in the waterborne polyurethane film. XRD demonstrated that the WPU segment was embedded in the middle of the PAE-MMT sheet, indicating the intercalation structure. Compared with pure WPU, when the mass fraction of PEA-MMT was controlled to be 3%, the tensile strength and Young's modulus were increased from 35 MPa and 13 MPa to 55 MPa and 44 MPa, respectively. Water resistance and oxygen barrier of composite were greatly improved by a synergistic effect of the lamellar structure of montmorillonite and the excellent interfacial interactions between PEA-MMTA nanosheets and WPU. When the mass fraction of PEA-MMT was increased above 3%, the water absorption and oxygen permeability of the nanocomposite films and coatings were reduced by 83% and 24%, respectively.
Construction of Osteoinductive and Biodegradable Chitosan-Coating on Titanium Surface and Regulation of Biological Activities
LI Haixia, HE Hongyan, DONG Xiulin, CHANG Lingxue, LIU Changsheng
 doi: 10.14133/j.cnki.1008-9357.20181219001
[Abstract](1638) [FullText HTML](177) [PDF 1655KB](7)
In order to improve the biological activity and promote the osteogenic differentiation capability of the implanted metallic materials, SLA-Ti was prepared from pure titanium (Ti) through sandblasting and acid etching (SLA). Then, ALN-SLA-Ti was formed by hydrophilic treatment on Ti with alendronate sodium (ALN). Chitosan (CS) was selected as the main material for the coating, ALN-SLA-Ti surface was coated with CS and immobilized protein by electrostatic spraying (ES). Human bone morphogenetic protein-2 (rhBMP-2) was rapidly and efficiently loaded onto the surface of ALN-SLA-Ti. Coatings loaded with active factors were constructed to enhance the biological activity of titanium surfaces. The morphology of the titanium surface was observed by scanning electron microscope. The result showed that ALN-SLA-Ti formed a microsphere structure after 5 min of ES. Bovine serum albumin (BSA) was used as a model protein to evaluate the release behavior in vitro. The adhesion and proliferation of cells on the surface of titanium was observed by laser confocal microscopy. Results showed that the treated surface had multi-level pore structures. Immobilized protein rhBMP-2 was continuously released in a contraled manner. CS coating with rhBMP-2 was conducive to cell adhesion and proliferation, and significantly promote osteogenic differentiation of cells.
Preparation of High-Strength Silk Fibroin/Polyethylene Glycol Cryogel
CHANG Huanliang, SHAO Changyou, MENG Lei, YANG Jun
 doi: 10.14133/j.cnki.1008-9357.20181112001
[Abstract](2214) [FullText HTML](323) [PDF 980KB](6)
A tough, porous silk fibroin (SF)/polyethylene glycol (PEG) cryogel was prepared through a simple freeze-thawing procedure by using PEG as cross-linking agent. Fourier-transform infrared (FT-IR) spectra, scanning electron microscope (SEM) and universal-testing machine were used to investigate the conformational change, micromorphology, mechanical properties, and swelling behaviors of cryogels. Results demonstrated that the incorporation of PEG faclitated the formation of crystal structures of SF chains, and the microstructure and mechanical properties can be tailored by freezing temperature, mass ratio of PEG to SF (mPEG/mSF), and SF mass fraction. When freezing temperature was −20 °C, wSF = 0.16, and mPEG/mSF=0.50, the compressive modulus of the SF/PEG cyrogels was up to 0.44 MPa and can tolerant large compressive strain (90%) without permanent deformation and fracture. The cryogel also demonstrated excellent elasticity recovery during cyclic compression test, and the Young’s modulus and toughness of cryogels could reach up to 4.15 MPa and 680.81 kJ/m3, respectively. The cryogels with homogeneously distributed inter-connected porous structure would promote their potential applications in tissue engineering field.
Advances in Zwitterionic Polymers
YAN Shupeng, ZHANG Chong, LYU Hua
 doi: 10.14133/j.cnki.1008-9357.20181210001
[Abstract](4175) [FullText HTML](1368) [PDF 2203KB](133)
Zwitterionic polymers are those that have both cationic and anionic charged moieties on the same side chain maintaining overall charge neutrality. Due to their ultra-hydrophilicity via electrostatically induced hydration and excellent biocompatibility, zwitterionic polymers have been extensively used in biomedical research. In this review, we first give a brief introduction to the physico-chemical properties, classification and synthesis of zwitterionic polymers. Specifically, we summarize the recent advances of zwitterionic polymers in the following fields. (1) Antifouling coatings: unlike traditional antifouling polymers, zwitterionic polymers generate a tightly bound and structured water layer around the zwitterionic head groups which offer better antifouling properties in complex environments. Moreover, the surface modification strategies are also discussed. (2) Modification of proteins: zwitterionic polymers have been applied to the modification of various kinds of proteins to increase the solubility and stability, inhibit the aggregation, enhance pharmacokinetics, reduce immunogenicity and mitigate the bioactivity loss of proteins. (3) Drug delivery system: due to their excellent hydrophilicity, biocompatibility and nonfouling properties, zwitterionic polymers have been used to increase the solubility and stability of drug carrier, extend the circulation time, and enhance the cellular internalization. (4) Membrane separation system: the fabrication and function of zwitterionic polymers in separation membrane are briefly discussed. Finally, we conclude with a perspective for the development of zwitterionic polymers in the future.
Fabrication of Cellulose Nanocrystals/Keratin Composite Film and Its Dye Adsorption Performance
QIAN Xunnan, ZHU Xiaoji, ZHU Weiming, YU Zhicheng, SONG Kaili
 doi: 10.14133/j.cnki.1008-9357.20190221001
[Abstract](2175) [FullText HTML](340) [PDF 1175KB](6)
An innovative biomass derived keratin composites was fabricated by adopting cellulose nanocrystals (CNC) as reinforcing building block and was used as adsorbent for dye removal. The resulting CNC/keratin composite film showed high mechanical strength and satisfying adsorption performance. The properties of CNC/keratin composite film were characterized. Adsorption behavior of the adsorbent was comprehensively studied. Results showed that the water resistance and tensile properties of CNC/keratin composite films were better than those of pure keratin membrane. The tensile strength and elongation of pure/keratin composite films were 2.7 MPa and 11%, respectively, and the mass loss in water was 30.5%. When m (CNC)∶m (keratin) = 5%, the tensile strength and elongation were increased to 15.0 MPa and 12.1%, respectively. When m (CNC)∶m (keratin) = 10%, the mass loss of CNC/keratin composite films in water was only 21.1%. The adsorption results showed that the CNC/keratin film exhibited higher removal efficiency and adsorption capacity for reactive brilliant blue KN-R dye than that of pure keratin film. The removal efficiency and adsorption capacity of 2.5%CNC/keratin composite film for reactive brilliant blue KN-R dyes reached 78% and 77.57 mg/g at pH 2, respectively. While, the removal efficiency and adsorption capacity of pure keratin film for reactive brilliant blue KN-R dyes were only 55% and 54.52 mg/g at pH 2, respectively. In addition, the adsorption process was in good agreement with Langmuir’s adsorption isotherm model and pseudo-second-order model.
Preparation of PEI Modified Magnetic Chitosan Microspheres and Their Adsorption Property for Ibuprofen
GAO Qi, HUANG Hailong, HAN Lu, XU Min
 doi: 10.14133/j.cnki.1008-9357.20190402001
[Abstract](2183) [FullText HTML](336) [PDF 904KB](9)
Magnetic Fe3O4 nano-particles were prepared by chemical coprecipitation method, and magnetic chitosan microspheres (Fe3O4@CS) and polyethyleneimine (PEI) modified magnetic chitosan microspheres (Fe3O4@CS/PEI) with different proportions were thereby prepared by Schiff base reaction in the emulsion system using glutaraldehyde as the crosslinking agent. The structure, particle size and magnetism of microspheres were characterized by infrared spectroscopy(FT-IR), X-ray powder diffraction(XRD), scanning electron microscope (SEM), dynamic laser scatter (DLS) and hysteresis loop. The adsorption amount of ibuprofen on microspheres and reuse rate were studied by ultraviolet spectrophotometer. The characterization results showed that the microspheres were successfully prepared by Schiff base reaction, which had no effect on the crystal phase of Fe3O4. The microspheres presented regular circle with narrow size distribution and were magnetic. The thermodynamics adsorption model of ibuprofen on microspheres was Langmuir adsorption isotherm, and the kinetic adsorption model was second order dynamics model. With the increase of PEI mass fraction, the adsorption amount of ibuprofen on microspheres were increased. When m(PEI)∶m(CS)=1∶1, the maximum adsorption amounts of ibuprofen on CP-3(Fe3O4@CS/PEI) was determined to be 138.63 mg/g by the Langmuir adsorption equation fitting, which was twice higher than that on CP-0(Fe3O4@CS). After repeated adsorption experiments for 5 times, the microspheres still showed good adsorption performance for ibuprofen.
Influence of CO2 on Acyl Compound Initiated Polymerization of 2-Pyrrolidone
CHEN Chen, CHEN Tao, ZHAO Liming, QIU Yongjun
$v.latestStateEn  doi: 10.14133/j.cnki.1008-9357.20190312001
[Abstract](2229) [FullText HTML](243) [PDF 942KB](7)
The influence of catalyst and CO2 on synthesis of bio-based poly(γ-aminobutyric acid) (PGABA) was investigated in the presence of acyl compound initiator. The molecular structure and crystal form of the products were examined using magnetic resonance spectroscopy (1H-NMR), Fourier transform infrared spectrometer (FT-IR), X-ray diffraction (XRD). Thermogravimetry (TG) and differential scanning calorimeter (DSC) were used to evaluate the thermal properties of PGABA samples prepared via different ways. The results indicate that the addition of CO2 had an adverse effect on the yield of PGABA. When the concentration of acyl catalyst was fixed at 6 mol% or 7 mol%, the molecular weight increased at first and then decreased with increasing CO2, while the yield decreased successively. When the concentration of catalyst was increased to 9 mol%, increasing CO2 less affected the molecular weight of PGABA, but the yield kept decreasing. On the other hand, the absence of initiator dramatically decreased the yield of PGABA in CO2 containing system. At different charge of CO2, the molecular weight rose firstly and then went down with increasing catalyst concentration. Such trend became not evidence at high charge of CO2. The effect of catalyst concentration on the yield was a little complex. The yield gave a maximum with increasing catalyst concentration when CO2 content was less than 13.2 mol%, above which a positive effect of catalyst on the yield was presented. The crystal of PGABA samples prepared through various method were all of α form and independent of the charge amount of catalyst, initiator and CO2. Moreover, introducing CO2 less affected the melting point of PGABA, but raised the thermal decomposition temperature which improved thermal stability of PGABA.
Progress in Bioadhesive Hydrogels
LIN Bozhong, ZHAO Li, WANG Hongwei, ZHU Haopeng, GAI Guangqing, WANG Liyan, DING Jianxun
$v.latestStateEn  doi: 10.14133/j.cnki.1008-9357.20190711001
[Abstract](2156) [FullText HTML](320) [PDF 6587KB](3)
Over the past few decades, the suture has been the practice of choice for wound management, which held the tissues in close proximity for fast healing and stop body fluid leakage. However, the suture is not ideal and not suitable for many procedures due to the inherent invasion of sutures. Complete sealing of incisions by sutures may cause additional damage to the surrounding tissues of the surgical sites. In addition, the incision closure using sutures requires a specific technical skill of the surgeons, which influences the duration and success of the operation. Moreover, the suture-enclosed wounds have a higher infection rate and face the subsequent removal of the suture. To solve these problems, medical adhesives have emerged as attractive alternatives to suturing due to their easy application. The medical adhesive is an atraumatic, fast, and painless method for wound management, which exhibits effective hemostasis, efficient prevention of body fluid leakage, strong tissue bonding, and minimal scarring. Surgical materials for medical adhesives should be biocompatible, biodegradable, and inexpensive. In this regard, bioadhesive hydrogels have attracted growing attention owing to excellent properties, including high adhesive strength and fast curing capability. Although considerable progress has been made in bioadhesive hydrogels, only few articles to date have reported on the preparation methods and adhesion mechanisms of bioadhesive hydrogels. This article summarizes the preparation methods of bioadhesive hydrogels. The adhesion mechanism of a bioadhesive hydrogel is usually the combination of multiple interactions with one interaction being dominant. In addition, the biomedical applications of bioadhesive hydrogels are introduced, and the development of bioadhesive hydrogels with unique properties is also predicted.
High Order Self-assembly of Dextran Nanogels Induced by Con A
XU Yuan, LIU Lingshan, WANG Hao, DOU Hongjing
 doi: 10.14133/j.cnki.1008-9357.20181124001
[Abstract](2691) [FullText HTML](572) [PDF 1139KB](14)
A dextran nanogel (Dex NG) with cross-linked structure was prepared through a grafting copolymerization induced self-assembly (GISA) strategy using water-soluble polysaccharide dextran as the main component. GISA is a method that combines free radical grafting polymerization and self-assembly into one step, and can realize large-scale preparation of nanogels. By using cerium ammonium nitrate (CAN) to create free radicals on dextran, methyl acrylate (MA) was initiated to polymerize at the site of free radical to form a grafting copolymer, and a subsequent formation of nanogel was induced by hydrophobic force originated from the resulting MA. Finally, diallyl disulfide (DADS) was added as a cross-linker to stablize the structures. The high order self-assembled nano-aggregates (Con A-Dex NG) were fabricated by Dex NG and concanavalin A (Con A) on the basis of the specific recognition between Con A and the glucose unit in dextran. The particle size, structure and morphology of the self-assembled nano-aggregates were characterized by transmission electron microscopy (TEM), dynamic laser light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (NMR) and isothermal titration calorimetry (ITC). The mechanism of high order self-assembly was also discussed. In addition, the cytotoxicity of free Con A and Con A-Dex NG on A549 cell (human lung cancer cell) was investigated. The results showed that the size of Con A-dextran nano-aggregates was directly related to the mass ratio of dextran nanogel to Con A. Moreover, the cytotoxicity experiments demonstrated that free Con A could inhibit A549 cells, and its biological activity did not show obvious variations during the process of high order self-assembly.
Preparation of Polyurethane/Nano-TiO2 Hybrid Materials Containing Alkyl Side Chains in Soft Segments
CHEN Pingping, ZHANG Nanjie, LI Zhongjun, XU Jun, HUANG Sheng, RUI Ping, ZHANG Jie
 doi: 10.14133/j.cnki.1008-9357.20190809001
[Abstract](2120) [FullText HTML](269) [PDF 1150KB](2)
Two well-defined comb-like polyester diols(GS)with C-18 side chains were synthesized by reacting glyceryl monostearate(GMS)with succinic anhydride. NCO-terminated polyurethane prepolymers with C-18 side chains in soft segment structure were synthesized from diphenylmethane diisocyanate(MDI), 1,4-butanediol(BDO)and GS, then polyurethane hybrid materials were further prepared by compounding with nano-TiO2. The structures of comb-like polyester diols and polyurethanes were characterized by 1H-NMR and FT-IR. The crystallization behavior, surface morphology and surface contact angles of the prepared polyurethane and its hybrid materials were characterized by DSC, WAXD, SEM, AFM and water contact angle measurements. The effects of alkyl side chain content and the amount of TiO2 on the surface properties of polyurethane and its hybrid materials were investigated. The results showed that the introduction of non-polar alkyl side chains into the polyurethane significantly reduced the surface energy, increased the contact angles of water on the surface, and reached the contact angle of water on the surface of the fluorine-containing polyurethane. In polyurethane/nano-TiO2 hybrid materials, the surface energy of the materials can be effectively adjusted to achieve superhydrophobicity of the surface by adjusting the content of soft segments(the number of alkyl side chains)and the amount of TiO2 in the structure.
Self-assembly and Photo-Responsiveness of Hyperbranched Azopolymers
TIAN Chen, Sun Liuying, TAO Xinfeng, YAO Yuan, LIN Shaoliang
 doi: 10.14133/j.cnki.1008-9357.20190510001
[Abstract](2330) [FullText HTML](395) [PDF 745KB](8)
A kind of hyperbranched azopolymers (HPAzoAMAM) with different structures and molecular weights were successfully synthesized via Michael Addition polymerization between A2 and B2B′ monomers. All the structures of HPAzoAMAM and their corresponding molecular weights were analyzed. The proposed HPAzoAMAM were found to self-assemble into aggregates with different morphologies and sizes in aqueous solution confirmed by SEM, TEM and DLS. Both the photo-isomerization of HPAzoAMAM in DMF and micelle solution were studied through UV-Vis spectrophotometer. The final results showed that the structure of HPAzoAMAM could be modulated by controlling the molar ratio of the initial A2 and B2B′ monomers. All the HPAzoAMAM could self-assemble into abnormal large spherical compound micelles (LCMs) with various sizes in aqueous solution because of their different hydrophilicities and molecular weights. Upon increasing the hydrophobicity and molecular weight of HPAzoAMAM, the size of LCMs turned to be larger. The reversible trans-cis isomerization behavior of HPAzoAMAM in DMF and micelle aqueous solution were studied by UV-Vis irradiation. The results showed that all the absorption peak of HPAzoAMAM solution in DMF were at the same positon of 377 nm, while that of the micelle solutions of HPAzoAMAM-1, HPAzoAMAM-2, HPAzoAMAM-3 were at 376 nm, 367 nm and 372 nm, respectively. Therefore, HPAzoAMAM aggregates were in different π-π stacking styles. Furthermore, in the case of HPAzoAMAM micelle isomerization, the time for reaching stationary state was much longer than that in DMF solution, which was attributed to the highly regular arrangement of azobenzene moieties in aggregates and the restriction of the hyperbranched structures. The feasible combination of azobenzene and hyperbranched polymer provides a promising guidance for the application research of azopolymers.
Effects of Periodic Micro-grooves on Surface of Polyetheretherketone/Mesoporous Calcium Magnesium Silicate Composite on Cell Behaviors
HAN Hang, RAMES Kaewmanee, SYED Asadullah, SHEN Xuening, PAN Yongkang, QIAN Jun, WANG Xuehong, WEI Jie
$v.latestStateEn  doi: 10.14133/j.cnki.1008-9357.20190617001
[Abstract](2147) [FullText HTML](254) [PDF 917KB](6)
Periodic micro-grooves with different widths (20, 40 μm and 60 μm) on the surface of polyetheretherketone (PEEK)/mesoporous calcium magnesium silicate (m-CMS) composite were prepared by femtosecond laser. The effects of width of micro-grooves on the adhesion, proliferation and differentiation of rat bone marrow mesenchymal stem cells (rBMSCs) were investigated. Results showed that the micro-nanostructures were formed in the inner surface of the micro-grooves after ablated by femtosecond laser, which exhibited a large number of mesoporous calcium magnesium silicate particles. In addition, the roughness (Ra = 5.15 μm) of the inner surface of the micro-grooves was significantly improved as compared with the grooved ridge (Ra = 1.53 μm) without treatment by femtosecond laser. Moreover, with the increase of the width of the micro-grooves, the protein adsorption of the composite surface was obviously enhanced, which significantly promoted the adhesion of rBMSCs on the composite surface. Furthermore, when the width of the micro-grooves was 20 μm, the cells did not display specific growth orientation on the composite surface. When the width of the micro-groove was 40 μm, a small number of cells grew along the groove orientation. When the width of the groove was 60 μm, a large number of cells grew along the groove orientation, and the cell body was plump with filamentous pseudopodia extending, which indicated that the composite surface not only significantly promoted cells adhesion, spreading, proliferation and osteogenic differentiation, but also induced cell growth along the groove orientation. In short, periodic micro-grooves on the composite surface were prepared by femtosecond laser, and the width of micro-grooves on the composite surface could regulate and control cells behaviors, in which appropriate width (e.g. 60 μm) of micro-grooves was conducive to stimulating cell responses.
Multiple Analytes Detection Based on Gold Nanoparticles and Fluorescent Oligonucleotides in One-Pot
ZHENG Bin, HE Kewu, CHENG Sheng, DONG Huaze, YU Yongqiang, HU Jinming
 doi: 10.14133/j.cnki.1008-9357.20190124003
[Abstract](2193) [FullText HTML](348) [PDF 3242KB](10)
Multiple analytes detection has been the main issue in the field of sensor. To achieve convenient preparation while retain the good sensitivity with little interferences, oligonucleotides (DNA) labelled by fluorescent dyes with different emission wavelengths were adopted as the sensing elements and gold nanoparticles (AuNPs) were selected as a quencher. In the presence of the target in the system, the formation of secondary structure induced by target binding onto aptamer will exclude fluorescent oligonucleotide from binding, releasing a signal-on sensor. Therefore, carboxyfluorescein (FAM) modified DNA adopted as the complementary strand for adenosine detection DNA and rhodamine (ROX) modified DNA complementary for potassium ions recognition DNA have been designed. It was observed that the detection range of adenosine was within 0−15 μmol/L with a detection limit of 387.9 nmol/L with the use of a 20 nmol/L recognition DNA, while the detection range can be enhanced to be 2−15 mmol/L with a recognition DNA concentration of 100 nmol/L. Therefore, the detection range can be simply tuned by changing the number of modified DNA on the surfaces of AuNPs. In the same way, the linear range of potassium ions was determined to be within 2−6 μmol/L and the detection limit was 1.6 μmol/L. Since the fluorescent signals of FAM and ROX present at 520 nm and 605 nm, respectively, the simultaneous detection of multiple analytes could be achieved by simply mixing and simultaneously detecting the fluorescence. The specificity of this method has also been verified using analogues controls. Adenosine could generate a signal with a strength of 5 folds higher than other structurally similar substances, while one third concentration of potassium ions of those analogues could create a signal with a strength of more than 2 folds than other similar ions.
Preparation of Poly-γ-Glutamic Acid/Chitosan Nanoparticles and pH Response Release Properties
REN Dongxue, CHEN Pengcheng, ZHENG Pu, XU Zhinan, LU Song
 doi: 10.14133/j.cnki.1008-9357.20181128001
[Abstract](2533) [FullText HTML](539) [PDF 1207KB](11)
The positively and negatively charged nanoparticles with pH responsiveness were manufactured by biocompatible poly-γ-glutamic acid (γ-PGA) and chitosan (CS) to load the antibiotic amoxicillin. The structures and morphologies of the drug-loaded nanoparticles were characterized by Dynamic Light Scattering (DLS), Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Diffractometer (XRD) and Transmission Electron Microscopy (TEM). The pH responsiveness of these nanoparticles to drug release and their toxicity to cells were investigated. Results showed that negatively charged nanoparticles displayed better ability of pH responsiveness to control drug release. Under simulated stomach environment, the sizes of the drug-loaded nanoparticles were 200—300 nm and the cumulative release of amoxicillin was only 25%. However, in the simulated intestinal cell gap environment which was neutral to weakly alkaline, the mean particle size increased to about 1 μm and the cumulative drug release was up to 85%. In addition, the nanoparticles were not toxic to cells, and the drug-loaded nanoparticles improved the inhibitory effects on intestinal bacteria compared to the free drug.
All-polymer Solar Cells Based on Acceptors Containing Non-planar Fused Perylene Diimide
HONG Yuwen, SHAN Tong, DING Kui, ZHONG Hongliang
$v.latestStateEn  doi: 10.14133/j.cnki.1008-9357.20190530001
[Abstract](2186) [FullText HTML](333) [PDF 1004KB](10)
Based on a non-planar fused perylene diimide unit (FPDI-Th), a new class of polymers PPDIBT-Th and PPDIBT-Th-C6 were designed and synthesized for the application as acceptors in all-polymer solar cells. Compared to PPDIBT-Th, hexyl side-chain was introduced into PPDIBT-Th-C6 to tune the molecular conformation. These two polymers were systematically studied by nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), UV-Vis absorption and cyclic voltammetry (CV) as well as the fabrication and measurement of all-polymer solar cell devices. Both of devices blending PPDIBT-Th or PPDIBT-Th-C6 with polymer donor PTB7-Th show good photovoltaic performance, indicating polymers containing FPDI-Th are promising acceptors for all-polymer solar cells. In addition, the introduction of side chain into polymers will decrease the planarity of back bone, leading to a weaker molecular packing and absorption intensity. However, our study reveals that the side-chains not only affect the properties of acceptor itself but also tune the molecular packing of polymer donor that is the other component in bulk heterojunction (BHJ). In the blend film, PPDIBT-Th with strong intermolecular interaction inhibits the aggregation of donor PTB7-Th, leading to an inferior morphology which has been verified by device performance and atomic force microscopy (AFM). Attributing to the balance of miscibility and crystallinity, all-polymer solar cells based on PPDIBT-Th-C6 and PTB7-Th displayed a higher short-circuit current density (Jsc) of 12.15 mA/cm2, eventually achieving a superior power conversion efficiency (PCE) of 4.95%.
Polypeptide-based Hollow Virus-like Particles: Preparation and Drug-loading Property
WANG Hongquan, XU Wenheng, ZHANG Shuo, JIANG Xiangyu, LI Hui, CHEN Jiachen, CAI Chunhua, LIN Jiaping
$v.latestStateEn  doi: 10.14133/j.cnki.1008-9357.20190424001
[Abstract](2318) [FullText HTML](334) [PDF 1341KB](7)
Virus-like particles (VLPs) have attracted increasing attentions in the field of drug-delivery. Ordered surface nanostructure is one of the essential structures of the natural virus. This work reports the preparation and drug-loading property of polypeptide-based hollow VLPs with ordered surface nanostructures. Starting from poly(γ-benzyl-L-glutamate)-block-poly(ethylene glycol) (PBLG-b-PEG) block copolymers, through deprotection of the benzyl group and subsequent esterification reaction, poly(γ-benzyl-L-glutamate-co-γ-cinnamyl-L-glutamate) -block-poly(ethylene glycol) (P(BLG/CLG)-b-PEG) block copolymers were synthesized, in which the cinnamyl group is photo-cross-linkable. The photo-cross-linking process of the P(BLG/CLG)-b-PEG block copolymers was tracked by UV-Vis spectrum. Adding water to the solution of P(BLG/CLG)-b-PEG block copolymer and PS homopolymers in THF/DMF mixture (1/1, v/v), spherical VLPs were self-assembled from the polymer mixtures. These VLPs contain a PS homopolymer core and P(BLG/CLG)-b-PEG block copolymer shell, and the P(BLG/CLG)-b-PEG block copolymers pack orderly forming strips on the surface. When replacing the PS homopolymers by rigid PBLG homopolymers, rod-like VLPs were obtained in which the PBLG homopolymers formed bundles and P(BLG/CLG)-b-PEG block copolymers self-assembled on the surface of the PBLG homopolymer bundles into helical nanostructures. Under UV-irradiation at λ = 254 nm, the P(BLG/CLG) blocks in the shell of both the spherical and the rod-like VLPs were cross-linked through the photodimerization of the cinnamyloxy groups. To the solution of the shell-crosslinked spherical VLPs, adding a large amount of DMF could remove the PS core forming hollow virus-like particles (HVLPs), and the strip patterns on the surface were retained. However, for the rod-like VLPs, under similar conditions, the PBLG homopolymers in the core could not be removed. Drug-loading capacity of the spherical HVLPs was evaluated by using doxorubicin (DOX) as a model drug. It was found that DOX was successfully loaded into the HVLPs with a high relative drug-loading content (230 wt%). Releasing studies revealed that the drugs can gradually release from the VLPs, and 72 hr accumulate releasing content reached about 80 wt %. This work provides a method to prepare polypeptide-based HVLPs with surface nanostructures, and these HVLPs could find applications for drug delivery.
Recent Progress in Colorless and Transparent Polyimide with High Thermal Stability
LAN Zhongxu, WEI Jia, YU Yanlei
$v.latestStateEn  doi: 10.14133/j.cnki.1008-9357.20190705001
[Abstract](2222) [FullText HTML](379) [PDF 3743KB](15)
Polyimides(PIs) have extensive applications in aerospace industry, microelectronic, optoelectronic engineering, liquid crystal display and separation membrane due to their high-temperature resistance, outstanding mechanical properties, chemical and radiation resistance and excellent dielectric properties. Conventional PIs possess strong inter- and intra- molecular charge transfer interactions, resulting in intense stack of the molecular chains, which leads to the strong absorption in the visible region and brings deep color to PI. This has considerably restricted their applications in the area of optoelectronic and microelectronic engineering. With the rapid development of display technology, PIs with excellent optical and thermal performance are desired to serve as substrate materials. However, achieving a breakthrough in the molecular design of the satisfied PI, particularly with regard to the trade-off between the good transparency and thermal stability of PI films, remains challenging because of the contradiction between the two properties. Recently, enormous research efforts have been devoted for the development of colorless and transparent PIs with high thermal stability by rational molecular structure design, which are summarized in this review. These fabrication strategies mainly include introduction of strong electronegative groups, alicyclic structures, bulky pendent units, asymmetric and rigid noncoplanar segments, and polymerizable inorganic nanoparticles. The incorporation of these structures plays important roles in disrupting the conjugation between the PIs chain, reducing the regularity and weakening the stack of the molecular chains, increasing the free volume of the PIs​​​​​​​ chain, prohibiting the formation of inter- and intra- charge transfer complex, which are beneficial to the decrease of absorption in the visible region and the formation of colorless PIs​​​​​​​. The influence of molecular structures on the properties of PIs​​​​​​​, such as thermal properties, optical performance and solubility, is discussed. Finally, the development trends and potential applications of colorless and transparent PIs​​​​​​​ with high thermal stability are predicted.
Synthesis and Gas Adsorption Properties of Carbazole-Functionalized Silole-Containing Microporous Frameworks
SHU Ge, LI Yuda, WANG Feng
$v.latestStateEn  doi: 10.14133/j.cnki.1008-9357.20190810001
[Abstract](2075) [FullText HTML](329) [PDF 1233KB](10)
A series of microporous organic polymer (MOPs) were synthesized by the one-step oxidative coupling reaction using carbazole-functionalized siloles, such as 1,1-dimethyl-3,4-diphenyl-2,5-bis(4'-(9H-carbazol-9-yl)-phenyl)silole, 1-methyl-1-phenyl- 3,4-diphenyl-2,5- bis (4'- (9H-carbazol-9-yl)-phenyl)silole and 1,1-diphenyl-3,4-diphenyl-2,5-bis(4'- (9H -car bazol -9-yl)-phenyl)silole. The structure and properties of the three MOPs were characterized by fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), thermogravimetric (TG) analysis scanning electron microscope (SEM) and Transmission Electron Microscope (TEM). FT-IR spectra indicated the success of the oxidative coupling reaction for constructing the polymer frameworks. PXRD measurements revealed that all the polymer frameworks were amorphous solid in nature. These MOPs exhibited high thermal stability with the onset of decomposition temperature above 400 ℃ at 5% mass loss under nitrogen flow. The nitrogen adsorption test showed that the specific surface area of the polymers Brunauer-Emmett-Teller (BET) ranged from 587 m2/g to 617 m2/g. There is a rigid main chain and nitrogen-rich conjugate structure of microporous skeleton material, the CO2 adsorption capacity of CPDM-CzS was 2.1 mmol/g at 113 kPa/273 K and the H2 adsorption capacity of CPPM-CzS was 1.51 wt% at 113 kPa/77 K. In addition, CPDM-CzS showed excellent selective gas adsorption performance of CO2/N2 of 75.22. These microporous frameworks will have potential application prospects in gas adsorption and separation.
Preparation and Properties of Polyurethanes from Poly(isosorbide dicarboxylate) Diols
CAO Baoren, XU Xianghong, WANG Guiyou
$v.latestStateEn  doi: 10.14133/j.cnki.1008-9357.20190619002
[Abstract](1920) [FullText HTML](318) [PDF 1404KB](14)
Firstly, a series of bio-based poly(isosorbide dicarboxylate) diols (PISA) were synthesized by the reaction between bio-based isosorbide (IS) and five kinds of dicarboxylic acids with different methylene chain lengths. Then bio-based polyurethanes (PUs) were prepared by the reaction of 4,4′-diphenylmethane diisocyanate (MDI) with PISA and 1,4-butanediol (BDO) as the chain extender. The structure and thermal properties of PISA samples were characterized by Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (1H-NMR) and differential scanning calorimeter (DSC). The results showed that Mn values of PISA were in the range of 672—940. As the carbon numbers in repeating units of PISA increased from 4 to 12, the glass transition temperature (Tg) of PISA samples decreased from 10.5 ℃ to −40.9 ℃. The viscosity also decreased, but the crystallinity improved. The structure and properties of bio-based PU samples were characterized by FT-IR, DSC, dynamic mechanical thermal analyzer (DMA), atomic force microscope (AFM), water contact angle test and measurement of mechanical properties. The results showed that when the length of methylene chain in the repeating unit of PISA increased, the hydrogen bonding of PU samples decreased. Tg values decreased from 114 ℃ to 71.4 ℃. The yield strength, Young's modulus and Shore D hardness decreased from 62.9 MPa, 2 042 MPa and 80 to 53.4 MPa, 1 070 MPa and 72, respectively. The hydrophilicity also decreased. However, the tensile strength and elongation at break improved appreciably from 36.0 MPa and 46% to 64.5 MPa and 220%, respectively. A new way to prepare bio-based PU materials with high rigidity and mechanical properties from bio-based isosorbide is provided.
Programmable Self-Assembly of Nanoparticles Non-Uniformly Functionalized with DNA Strands
GU Mengxin, ZHANG Liangshun, LIN Jiaping
$v.latestStateEn  doi: 10.14133/j.cnki.1008-9357.20190429003
[Abstract](2360) [FullText HTML](344) [PDF 832KB](14)
DNA-functionalized nanoparticles, regarded as the programmable atom equivalent, enable the realization of hierarchically self-assembled superstructures. The self-assembled superstructures, which possess unique mechanic, optical and electronic properties, have prospective applications in the field of energy conservation, catalysis and medical diagnostics. Uniformly DNA-functionalized nanoparticles, whose self-assembly behavior has been well studied, self-assembly into two- and three-dimensional nanoparticle superlattices. With the development of nanotechnology, non-uniformly DNA-functionalized nanoparticles with DNA strands regioselectively distributed on the surfaces are successfully synthesized. Recently, by utilizing the non-uniformly DNA-functionalized nanoparticles, researchers have realized nanoparticle superstructures with complex architecture in experiments, such as discrete planet-satellite nanostructures, one-dimensional nanoparticle chains or even three-dimensional networks. However the mechanism and design rules of self-assembly of non-uniformly DNA-functionalized nanoparticles remain to be explored. Herein, the coarse-grained model of non-uniformly DNA-functionalized nanoparticles is constructed, and molecular dynamics is utilized to simulate the self-assembly process of DNA-programmable nanoparticles. It is demonstrated that the non-uniformly DNA-functionalized nanoparticles self-assemble into the branched or even network-like superstructures through the hybridization of complementary DNA strands. The geometrical model of self-assembled superstructures is proposed to predict the relative position and distribution of nanoparticles inside the superstructures. Sparked by the molecular polymerization, we further explore the effect of the stoichiometric ratio on the self-assembly of nanoparticles. The stoichiometric ratio of nanoparticles has a remarkable effect on both the architecture of superstructures and the kinetics of DNA-programmable self-assembly of nanoparticles. As the stoichiometric ratio increases from 1.0 to 5.7, the self-assembled superstructures switch from the spanning networks to discrete branched clusters. These findings will help the experimentalists to rationally regulate the self-assembly kinetics and design the assembled superstructures of DNA-functionalized nanoparticles.
Research on Degradable Polyurethane Bone Adhesive
ZHU Qi, LEI Kun, ZHENG Zhen, WANG Xinling, XIAO Haijun
$v.latestStateEn  doi: 10.14133/j.cnki.1008-9357.20190226001
[Abstract](2155) [FullText HTML](330) [PDF 969KB](12)
Bone adhesive provides a simple and convenient method for the treatment of bone fractures. It is not necessary to remove of the metal implants. Polyurethane is a kind of material with good biocompatibility, physical and mechanical properties, and has a wide range of applications in medical fields. In this context, we designed a two-component polyurethane adhesive system and investigated its feasibility as a bone adhesive by in vitro experiments. Briefly, polyester triol was successfully synthesized with ε-caprolactone, glycolide and DL-lactide as the monomers, glycerol as the initiator and stannous octoate as the catalyst. The synthesized polyurethane triol was then reacted with isocyanate terminated prepolymer to form the polyurethane adhesive. The chemical structure of the polyester triol and polyurethane adhesive were characterized by nuclear magnetic resonance (1H-NMR) spectroscopy and Fourier transform infrared (FT-IR) spectroscopy. Surface morphology, mechanical properties and thermodynamic properties of polyurethane adhesives were evaluated by scanning electron microscopy (SEM), universal tensile testing machine, and differential scanning calorimetry (DSC). (The degradation rate of polyurethane adhesive was tested by placing polyurethane disks in a 10 mL glass vial filled with 0.1 mol/L phosphate buffer saline (PBS) solution at pH 7.4.) The effect of polyestertriol molecular weight and the incorporation filler on the properties of polyurethane adhesives were explored. The results showed that the PU-6C400-F group presented good compressive performance with a bonding strength of 0.93 MPa, and with a compressive strength and modulus of 12.5 MPa and 128 MPa, respectively. These results demonstrated that the polyurethane adhesive could be a good candidate for bone gluing applications.
Preparation of Nitrogen-Doped Graphene Films for Surface-Enhanced Raman Scattering
ZHENG Nannan, YUE Yuchen, SHEN Yongtao, FENG Yiyu, FENG Wei
 doi: 10.14133/j.cnki.1008-9357.20190424002
[Abstract](2764) [FullText HTML](558) [PDF 1149KB](10)
Graphene is a zero-gap semiconductor with low work function and high leakage current which limits its application. The doping of nitrogen is one of the way to tailor the properties of graphene. However, there remains some shortcomings, such as low nitrogen content and poor controllability. In order to enhance the content of nitrogen and control the bonding characters for embeded nitrogen atoms within the carbon lattice, solid-state sources (melamine) and gas-state source (methane) were used to prepare nitrogen doped graphene films (NG). The preparation time, the dosage of melamine as well as the temperature of catalyst were set as tunable parameters. The morphology of NG, the content of nitrogen and the bonding characters for embeded N atoms were studied. The results indicate that the preparation process of NG films includes nucleation, growth and aggregation. Proper temperature (990 ℃) are conductive to improve the content of nitrogen. Pyrrolic N is tend to produced at high temperature (>1000 ℃), while graphitic N is the opposite. With increasing the dosage of melamine, the content of nitrogen increased and then decreased with the maximum value for 6.98 at%. The content of Pyridinic N will be promoted with increasing the amount of melamine. Compared with graphene, NG films can detect the Raman signals from Rhodamine B molecules even for concentrations as low as 10−5 mol/L.
Porous Carbons Pyrolyzed by Casein and Their Performance for Supercapacitor
XIAO Jianwei, XIAO Guyu
$v.latestStateEn  doi: 10.14133/j.cnki.1008-9357.20190422001
[Abstract](2297) [FullText HTML](349) [PDF 1516KB](5)
Many porous carbon materials derived from biomass were high performance electrode materials for supercapacitor. The natural macromolecule of casein was utilized as the precusor of carbon materials. It was mixed with phytic acid in the acid solution, thus forming the acid-base cross-linking between them. The mixtures were pre-carbonized at low temperature and further activated by KOH at high temperature, achieving porous carbon materials. These carbon materials exhibited a high specific surface area of up to 3 567 m2/g and were considered as an excellent electrode material for supercapacitors. Their electrochemistry properties were characterized by both three-electrode and two-electrode system in alkaline electrolyte. In a three-electrode system, the specific capacitance was as high as 411 F/g at 1 A/g. In a two-electrode system, the specific capacitance was up to 235 F/g at 1 A/g and still remained 231 F/g after 8 000 charge-discharge cycles at 5 A/g. Results revealed that these porous carbon materials displayed high capacitance and outstanding cycling stability. These carbon materials exhibited better performance for supercapacitor in comparison with most carbon materials pyrolyzed by natural macromolecules. Moreover, this facile and efficient route could be used for fabricating high performance porous carbon materials.
A Low Bandgap Aza-Fused Conjugated Microporous Polymer for Photocatalytic Dye Degradation
ZHANG Hang, WANG Lei, CHENG Hao, XU Hangxun
$v.latestStateEn  doi: 10.14133/j.cnki.1008-9357.20190424004
[Abstract](2685) [FullText HTML](502) [PDF 1245KB](15)
Semiconductor photocatalysts can directly use sunlight to produce clean and renewable energy, offering a potentially viable solution for addressing energy and environmental crisis. Recently, conjugated microporous polymers have emerged as a very promising class of materials in solar energy conversion. However, they generally exhibit low catalytic efficiency and insufficient catalytic stability. Moreover, they also lack of the capability to utilize long-wavelength photons in the near-infrared region. In this work, we synthesize aza-fused conjugated microporous polymer (aza-CMP) via condensation of 1,2,4,5-benzenetetramine and cyclohexanone. The as-obtained aza-CMP exhibits a band gap as low as 1.22 eV ensuring that it can absorb both visible light and near infrared photons. Meanwhile, we show that aza-CMP can effectively drive the degradation of various organic dyes such as Congo Red, Rhodamine B, and Methyl Orange under visible and near-infrared light irradiation. In contrast, other photocatalysts such as P25-TiO2, g-C3N4, and Ag-TiO2 are unable to oxidize organic dyes under near-infrared light irradiation, suggesting that aza-CMP is very efficient in absorbing visible and long-wavelength photons for photocatalytic oxidation of organic pollutants. In addition, multiple cycling experiments confirm that aza-CMP is very stable during the catalytic process, which can retain its structure and high catalytic activity after multiple cycles. Mechanistic investigations further reveal that the active species toward photocatalytic degradation of organic dyes are the photogenerated holes and singlet oxygen. Furthermore, the pathways of the photocatalytic degradation of organic dyes are unveiled by using liquid chromatography-mass spectrometry (LC-MS), clearly demonstrating the capability of aza-CMP in oxidizing organic dyes into small molecules. This study potentially provides new prospects in design and synthesis of conjugated polymers for various photocatalytic applications.
Preparation and property of PEGylated melampomagnolide B prodrug nanoparticles for cancer therapy
QU Wenhao, YANG Quanjun, HUANG Ping, HUANG Wei, YAN Deyue
$v.latestStateEn  doi: 10.14133/j.cnki.1008-9357.20190424003
[Abstract](2657) [FullText HTML](638) [PDF 1108KB](17)
Melampomagnolide B (MMB) is one of parthenolide (PTL) derivatives with the high anticancer activity to various tumors. However, its application in clinic is limited due to the poor water solubility. To overcome this problem, an amphiphilic prodrug is synthesized from carboxyl polyethylene glycol monomethyl ether (mPEG10-COOH) and MMB through an esterification reaction. The chemical structure of mPEG10-MMB is confirmed by nuclear magnetic resonance (NMR) and liquid chromatography-mass spectrometry (LC-MS). The amphiphilic prodrug mPEG10-MMB can self-assemble in water with the critical micelle concentration of 7.7 μg·mL-1 and the size/morphology of its assemblies is characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The DLS result indicates that an averaged size of mPEG10-MMB nanoparticles is about 120.3 nm with a narrow distribution. The TEM image exhibits mPEG10-MMB can self-assemble into spherical nanoparticles with an average diameter of 108.5 nm. Nile red (NR) is used as the fluorescent probe and loaded in mPEG10-MMB prodrug nanoparticles. The flow cytometry and confocal laser scanning microscope (CLSM) are used to evaluate the cell uptake of mPEG10-MMB prodrug nanoparticles. The results demonstrate that mPEG10-MMB prodrug nanoparticles can be internalized by HeLa cells efficiently through the endocytosis mechanism. In vitro cytotoxicity of mPEG10-MMB prodrug nanoparticles is evaluated against HeLa cells and BRL-3A cells by MTT assay. The result demonstrates that mPEG10-MMB prodrug nanoparticles have higher cytotoxicity to cancer cells compared to that of free MMB, but relatively lower cytotoxicity to normal cells.
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Advances in Chiral Assembly of Achiral Substance Induced by Chiral Oligomer/Polymer
CHENG Xiaoxiao, MIAO Tengfei, YIN Lu, CHEN Hailing, LIU Meng, ZHANG Wei, ZHU Xiulin
2019, 32(6): 647-659.   doi: 10.14133/j.cnki.1008-9357.20190329001
[Abstract](2748) [FullText HTML](586) [PDF 2718KB](35)
The chiral oligomers/polymers are usually used as the scaffolds or templates to induce the helicity/chirality of achiral substances, which has been one of the research hotspots in recent years. Compared to traditional methods, this method can not only avoid the use of expensive chiral reagents and complex synthetic routes, but also enrich the types of chiral substances, which has potential applications in bioscience, especially in the field of exploring the origin of chirality. In this review, we briefly introduce the historical development of chiral assembly of achiral substances induced by natural/synthetic chiral oligomers/polymers. Additionally, the advances in chiral assembly of achiral polymers and inorganic compounds induced by chiral oligomers/polymers scaffolds (templates) strategies are also discussed. The research focuses and development trends of this method are summarized in the end. With implications for biological helices and functions, further applications of chirality-responsive polymers based novel chiral materials as enantioselective catalysts and adsorbents will be an interesting and important challenge. In the future, oligomer/polymer scaffolds (templates) strategies will receive much more attention from scientists in the fields of photoelectric materials, chiral resolution, enantiomeric sensors and asymmetric polymerization.
Homo-Chiral and Hetero-Chiral Interaction Regulate on Supramolecular Polymers
ZHANG Li, FAN Huahua, LIU Minghua
2019, 32(6): 660-670.   doi: 10.14133/j.cnki.1008-9357.20190527001
[Abstract](2324) [FullText HTML](389) [PDF 2762KB](15)
Chirality is the basic feature of nature. Chiral molecules are one of the important structural elements of life and play a unique role in maintaining many biological structures and functions. Therefore, it is of great significance to understand the role of chirality, especially supramolecular chirality, in the view of mimicking chiral structures, such as DNA and proteins, in biological system. Chiral supramolecular polymers, which are formed by components via various noncovalent interactions and the components in those assemblies exhibit the non-symmetric spatial arrangement, are good models to gain sight on the formation and functions of chiral biostructures. The formation of chiral supramolecular polymers is strongly related to both the chirality of the molecular components and their assembly routes. Therefore, it is possible that all kinds of molecules, either chiral or achiral (including racemic mixture), can assemble into chiral nano/microstructures through non-covalent bonds. In this mini-review, we mainly focus on the self-assemblies in the racemic mixture of two enantiomers. The chiral interactions, such as homo-chiral interaction and hetero-chiral interaction, play a subtle role during the formation of supramolecular polymers. The self-sorting assembly originated from homo-chiral interaction (ESS or ERR (interaction between the same enantiomers) >ESR (interaction between the different enantiomers)) and self-reorganized assembly originated from hetero-chiral interaction (ESS or ERRESR) are reviewed. The chiral sense of formed nanostructures and length of supramolecular polymers can be tuned by controlling the homo-chiral or hetero-chiral interactions. Further, the stereoselective energy transfer has been introduced as an example of chirality-driven function of supramolecular polymers.
Recent Progress in Chiral Materials with Induced Circularly Polarized Luminescence
LI Qingxiang, LIANG Hongyu, LU Xuemin, LU Qinghua
2019, 32(6): 671-682.   doi: 10.14133/j.cnki.1008-9357.20190719001
[Abstract](2445) [FullText HTML](361) [PDF 3044KB](14)
Because circularly polarized luminescence(CPL) has unique properties including extensive optive information, large-capacity optical information and angular independence, chiral materials with CPL emission present increasing potential for applications in diverse fields such as storage of information, bio-encoding, 3D optical displays and even catalysts for asymmertirc photochemical synthesis. As an important approach, supramolecualar self-assembly can provide a convenient method to construct the CPL materials by introducing chiral source and achiral fluorescent moleculars into the supramolecular system through different nocovalent interactions (such as π-π stacking, electrostatic interactions and hydrogen bonding). The chiral arrangement of the luminescent units in the assembly plays a key role in controlling the CPL emission (including the intensity and sign) of such materials. Although the study of CPL materials lasts several years, an open question that has long been a point of concention is how to achieve the high performance CPL materials. A high degree of dissymmetry ratio is also the urgent challenge. Therefore, it is vital to develop effective ways for the CPL materials with the high dissymmetry factor. In this review, we focus on the present progress on the chiral materialswith induced CPL emission by using template including chiral gel nanotube, mesoporous template, liquid crystalline polymer and helix formed by polymer. The dissymmetric factor and luminescent intensity of the obtained CPL materials in different assemblies were intensively discussed depending on different templates. We also present some perspective on the development of the induced CPL materials and the future application.
Research Progress on Living Polymerization of Allenes Catalyzed by Nickel Complexes
KANG Shuming, SONG Xue, ZHOU Li, WU Zongquan
2019, 32(6): 683-695.   doi: 10.14133/j.cnki.1008-9357.20190618001
[Abstract](2708) [FullText HTML](417) [PDF 2196KB](20)
Allene derivatives have cumulated double bonds and can be regarded as the isomers of propargyl derivatives. Due to their unique structures with 1,2-cumulative double bonds, they can exhibit special reactivity and can selectively conduct 1,2- or 2,3-position polymerization under appropriate conditions. Taking advantage of this characteristic, polymers with exomethylene substituents can be obtained through the selective polymerization of either part (1,2- or 2,3-)of the cumulated double bonds. Allylnickel( II)complexes and poly( 3-hexylthiophene)( P3HT)have been reported to promote the living/controlled polymerization of allene derivatives. The polymerization of allene using the catalysts such as allylnickel( II)complexes and poly( 3-hexylthiophene)( P3HT)is presented with detailed discussion, including the impact of the substituents on the monomers, the reaction solvent during the polymerization using allylnickel( II)complexes as catalyst, the application of living polymerization of allene using different allylnickel( II)complexes, and the self-assembly performance of polyallenes using P3HT as catalyst. In addition, living polymerizations of chiral allene monomers with allylnickel complex as a catalyst afforded helical polyallenes was also described. The helical structure of the polyallenes was quite stable with a preferred handedness in aprotic solvents. The helical polyalkenes behaved pH-responsive property due to the amino group on the pendant.
Recent Progress on Pore-Containing Helical Polymer Materials
WANG Ying, CHEN Xinyuan, LI Wencan, ZHANG Chenyang, DONG Zeyuan
2019, 32(6): 696-704.   doi: 10.14133/j.cnki.1008-9357.20190612001
[Abstract](2227) [FullText HTML](348) [PDF 1971KB](12)
Porous materials display many important applications in our daily life. Usually, the applications of porous materials largely depend on the properties and structures of the pores. Although the study of porous materials has been of several decades, the features and functions of porous materials are still unpredictable. Indeed, the function-directed design of porous materials remains challenging. A " bottom-up” preparation method will be promising to make progress in the filed of porous materials, wherein porous materials are composed of preorganized pore structures. Therefore, it is crucial to create preorganized pores for the preparation of porous materials. Recently, pore-containing helical polymers have been developed as specific advanced functional polymer materials, and have attracted much attention owing to their potential applications in various fields such as molecular recognition, isomer separation, asymmetric catalysis, sensing, enantioseparation, delivery, and sequencing. Typically, these helical structures were spontaneously formed by folding of polymeric chains driven by intramolecular noncovalent interactions, such as hydrogen bonding, electrostatic interactions, and π-π interactions. In general, the pore structures strongly relied on the stability of helical conformation, thus the helical polymers with rigid backbones were required. The pore-containing helical polymers can be further used as preorganized pore structures for the preparation of porous materials through a " bottom-up” preparation approach. In this review, the recent progress on pore-containing helical polymer materials is outlined. In particular, the structural features and designing strategies of pore-containing helical polymers will be emphasized, and a few examples on pore-containing helical polymers have been highlighted. Additionally, these helical polymers show very important properties, such as biomimetic transmembrane transport, and can be applied in the development of advanced membrane materials.
Supramolecular Assembly of Amino Acid Containing Silole Molecules
XIA Qing, YUAN Qin, Jason C Y NG, TANG Benzhong, LI Bingshi
2019, 32(6): 705-710.   doi: 10.14133/j.cnki.1008-9357.20190425001
[Abstract](2810) [FullText HTML](490) [PDF 2001KB](21)
The chirality of amino acid containing aggregation induced emission molecule silole (SI) has successfully transferred from the pendant to the silole scaffold. Chirality of the amino acid attachments can not only induce helical conformation of the molecules, but also be amplified as helical assemblies on the higher order architectures of the molecules. The self-assemblies were determined by both the chemical structures of the molecules and the surfaces/interfaces of the molecules. With the employment of atomic force microscope and Langmuir-Blodget technique, the self-assembly of the molecules on the surface of mica and on the air/water interface upon the evaporation of the solvent toluene was studied, respectively. The molecules self-assembled into helical fibers, while self-assembled into aligned ridges on the air/water interface at lower surface pressure, and with aligned nanofibers absorbed on the film at high surface pressure. In toluene the molecules formed intermolecular hydrogen bonds, which stabilized helical assemblies. The hydrogen bonds were patterned in a dislocation way due to the propeller shape of the molecules and the chirality of the amino acid attachments. On the air/water interface hydrogen patterns failed to form due to the lateral affinity between the amino acid attachments and water, and the hydrophobic repulsion between silole scaffold and water. Film of aligned ridges was formed with aligned fibers attaching to the surface of the aligned ridges. The aligned fibers had the same orientation with the underlying substrate mica, suggesting that the surface also played a critical role in determining the morphology of the assemblies.
Synthesis and Characterization of an Aggregation-Induced Emission-Active Polymer with Amino Acid-Containing Side Chains
ZHANG Wan, CAI Xinye, LI Hongkun, LI Yongfang
2019, 32(6): 711-717.   doi: 10.14133/j.cnki.1008-9357.20190729002
[Abstract](2457) [FullText HTML](358) [PDF 1211KB](25)
A dibromo aryl monomer (1) bearing L-valine methyl ester group was synthesized by the Cu(I)-catalyzed azide-alkyne click reaction. The Sonogashira polycoupling between 1 and tetraphenylethene (TPE)-containing diethynyl monomer (2) was then carried out, affording a soluble TPE-based conjugated polymer P (TPE-Val) decorated with chiral amino acid-containing side chains. The structure of the polymer as characterized by Fourier transform-infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), and thermo gravimetric analyzer (TGA). The properties of the polymer were investigated by fluorescence spectroscopy, circular dichroism spectroscopy, and scanning electron microscopy (SEM). The emission of the polymer is very weak in its dilute solution, but turns to be very high in the aggregated state, showing aggregation-induced emission (AIE) characteristics. Furthermore, the polymer gives circular dichroism (CD) signals in the aggregated state, and has the capacity to self-assemble into helical nanofibers.
Supramolecular Chiral Assembly of Achiral Hyperbranched Polyfluorenes Induced by Rigid Rod-Like Chiral Polysilanes
CHEN Hailing, CHENG Xiaoxiao, MIAO Tengfei, LIU Meng, LI Jieai, ZHANG Wei, ZHU Xiulin
2019, 32(6): 718-727.   doi: 10.14133/j.cnki.1008-9357.20190520002
[Abstract](2316) [FullText HTML](385) [PDF 2696KB](19)
The synthetic chiral polysilane adopts a rigid rod-like spiral structure, which has unique circular dichroism (CD) characteristics in near ultraviolet (UV) region and can be easily decomposed by UV irradiation. Therefore, chiral polysilanes have become excellent chiral scaffolds for inducing supramolecular chiral assembly of achiral polymers in recent years. In order to further verify the chiral scaffolding capability of chiral polysilane and enrich the types of achiral or optically inactive polymers that were induced to perform supramolecular chiral assembly, hyperbranched polyfluorenes (HPF8s) with different branching units were synthesized on the basis of Suzuki polycondensation reaction, which laid a foundation for further realization of chiral supramolecular assembly of hyperbranched main-chain conjugated polymers induced by using chiral polysilanes as the chiral scaffolds. The supramolecular chiral assembly of HPF8s was successfully induced by an enantiomeric pair of rigid rod-like helical polysilanes bearing (S)- and (R)-2-methylbutyl groups (PSi-S(R)) in a binary solvent mixtures of chloroform and methanol. Optimizing experimental conditions were crucial for boosting the CD amplitudes of HPF8/PSi-S and HPF8/PSi-R hetero-aggregates. The effects of various conditions on the supramolecular chiral assembly behavior of hyperbranched polyfluorenes induced by chiral polysilanes were systematically investigated. Results showed that the choice of cosolvent, the volume ratio of good and poor solvent, the mass concentration ratio of HPF8s to PSi-S(R), and the branching unit content of HPF8s presented great impacts on the chiral expression of the hetero-aggregates. In addition, the optically active HPF8s homo-aggregates were produced by complete photoscissoring reactions at 313 nm, which could be assigned to the Siσ-Siσ* transitions of PSi-S and PSi-R.
Supramolecular Chiral Gel Based on Triazole-Modified Triphenylene Derivative
ZHANG Hongli, CHENG Junjie, ZOU Gang
2019, 32(6): 728-734.   doi: 10.14133/j.cnki.1008-9357.20190611001
[Abstract](2275) [FullText HTML](348) [PDF 1936KB](10)
Supramolecular gels are formed by the self-assembly of small organic molecules of which the self-assembled nanostructures are entangled to form a 3D network. During the self-assembly, gelator-solvent interactions are able to subtly regulate these interactions and play an important role during the gel formation. In this paper, we synthesized several triphenylene derivatives and lucubrated the necessary conditions for gel formation by adjusting the molecular structures of the triphenylene derivatives and the polarity of the organic solvent. Low polarity of organic solvent is favorable for supramolecular assembly. Furthermore, the triazole-modified triphenylene derivatives are easier to form a gel by self-assembling in non-polar solvent, but longer flexible chains result in unstable gels. Besides, another triphenylene derivative that the flexible chain is linked by an ester bond cannot form supramolecular gel. It indicates that the dipole-dipole and π-π interactions between 1,2,3-triazoles play a synergic effect on gel formation, which stabilize the columnar assembly of triphenylene moiety. Furthermore, shorter flexible chain can increase the stability of the resulting supramolecular gel. On this basis, (+)- or (−)-limonene is introduced as a chiral solvent during the self-assembly process of triazole-modified triphenylene derivative. As a result, a specific optically active supramolecular chiral gel is formed successfully, and the optically activity of the supramolecular assembly is maintained after removing limonene.
Preparation and Enantioseparation Performance of Mixed-Type Polysaccharide-Based Chiral Stationary Phases
BI Wanying, PIAO Hexiang, LIU Bo, LI Geng, SHEN Jun
2019, 32(6): 735-740.   doi: 10.14133/j.cnki.1008-9357.20190531001
[Abstract](2332) [FullText HTML](375) [PDF 1861KB](17)
Amylose tris(phenylcarbamate) (A1), cellulose tris(phenylcarbamate) (C1) and cellulose tris(3,5-dimethyl phenylcarbamate) (C2) were synthesized by " one-pot” method. The structures of the derivatives were quantitatively characterized by 1H-NMR. The regular structure and complete substitution of the derivatives were confirmed. The obtained amylose and cellulose derivatives were then coated on the macroporous silica gel, giving rise to mixed-type chiral stationary phases (CSPs) by two mixing ways. Their enantioseparation abilities for ten chiral compounds were evaluated by HPLC. The chiral recognition abilities of the obtained mixed-type CSPs were compared with those of several single polysaccharide-based CSPs (commercialized coated-type CSP derived from C2), including A1, C1 and Chiralcel OD. The results showed that the mixed-type CSPs, especially those mixing with A1 and C2, exhibited higher enantioseparation performance for some chiral compounds, which could be ascribed to the combined enantioseparation abilities derived from the cellulose and amylose derivatives with different higher order structures in the mixed-type CSPs. The mixing methods, either before or after coating process, had no remarkable influences on the chiral recognition ability of the obtained CSPs. However, some mixed-type CSPs showed decreased enantioseparation abilities for a few chiral compounds, which have opposite elution orders on the two single CSPs. This work suggests that the mixed CSPs is probably more efficient for the improvement on the chiral recognition abilities in case both single CSPs follow the similar recognition mechanism.
Synthesis and Anion Recognition Ability of Helical Poly(phenylacetylene) Bearing L-Alanine Derivative Pendants
ZHU Ruiqi, SUN Jun, ZHOU Yanli, ZHOU Zhengjin, QIU Yuan, LIU Xudong, ZHANG Chunhong
2019, 32(6): 741-746.   doi: 10.14133/j.cnki.1008-9357.20190607001
[Abstract](2159) [FullText HTML](299) [PDF 1144KB](9)
Anion recognition is closely related to human life activities and of great significance to human life and its social progress. Therefore, the recognition of anions in high-performance has been the focus of research in recently years. Poly(phenylacetylene) derivatives possessing helical conformation in main chains have good optical activity and unique properties, and have potential applications in anion recognition and luminescence materials. In this work, a novel substituted poly(phenylacetylene) derivative containing amino acid and group with the function of anion recognition was synthesized, and optical activities and anion recognition abilities of the polymer were also investigated. L-alanine residue and amide group having anion recognition ability were introduced to phenylacetylene monomer, and phenylacetylene monomer (PAA-L-Ala) with optical activity was successfully synthesized via amidation reaction, deprotection of Boc group and amidation reaction. The phenylacetylene monomer was successfully polymerized in DMF (N,N-dimethylformamide) using a rhodium catalyst to yield a optically active poly(phenylacetylene) derivative (PPAA-L-Ala). The optical activities of polymer and monomer were investigated by the specific rotation and circular dichroism. The results show that the back bone of the polymer possesses a dynamic helical conformation induced by the asymmetric chiral residue. The anion recognition ability of the novel poly(phenylacetylene) derivative was evaluated using a series of tetra-n-butylammonium salts in DMF. The results indicate that PPAA-L-Ala has anion recognition ability, which can be used as a probe for selective recognition of AcO, \begin{document}${\rm {H_2}P{O_4}^{-}}$\end{document}, OH and F based on circular dichroism or fluorescence spectrometer, and a probe for selective recognition of OH and F based on naked eyes and UV-Vis.
Solvent-Depended Helicity Inversion of Polyphenylacetylene in Chiral Induction of Polyphenylacetylene Bearing Diphenyl Pendants
GU Yuanyuan, WANG Yaodong, WANG Yan, LIU Lijia
2019, 32(6): 747-754.   doi: 10.14133/j.cnki.1008-9357.20190529001
[Abstract](1977) [FullText HTML](352) [PDF 1060KB](12)
Achiral (4-(dodecyloxy)-4'-ethynyl-[1,1'-biphenyl]-3,5-diyl) dimethanol (PhDHPA) was synthesized, and then was polymerized under the cataysis of an achiral rhodium catalyst, the chemical structures of intermediate compounds and PhDHPA monomer were characterized by nuclear magnetic resonance spectroscopy (1H-NMR), and the molecular weight and dispersion coefficient of the Poly(PhDHPA) were determined by gel permeation chromatography (GPC). The resulting Poly(PhDHPA) was achiral, however, when chiral bias such as R-(+)-1-phenylethanol, S-(-)-dimethyl-1-butanal, L-menthol, and R-phenylethylamine, was added in the solution of Poly(PhDHPA), it showed clear circular dichroism (CD) signals in the absorption regions of the polyphenylacetylenes backbones. The sign and pattern of the induced CD signals showed the dependence on the type of chiral bias and the solvent in the system. These indicate that one-handed helix structure could be successfully induced on the main chain of Poly(PhDHPA) by the chiral bias. The chiral induction might be due to the inter-molecular hydrogen bonds or π-π stacking interactions between the polymer with the chiral bias. It is interesting that merely change the solvent caused the helix inversion of the polymer even under the same chiral bias, and the influences of solvent and chiral bias on the induced helical structure of Poly(PhDHPA) in the solution were systematically investigated. The CD-UV/Vis spectra of Poly(PhDHPA)/L-menthol in different solvents was performed at the temperature region from −10 ℃ to 50 ℃, indicating that the helical structure induced by L-menthol showed good thermostability.