• ISSN 1008-9357
• CN 31-1633/O6
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Flexible sensors have potential applications in the fields of wearable devices, implantable devices, and electronic skin, etc. Polymer hydrogels have biomimetic mechanical properties and biocompatibility, and thus are widely recognized as promising candidate materials for biomimetic flexible devices. Conductive hydrogels, including electron conductive and ion conductive hydrogels, have been widely developed as fundamental materials for flexible sensors. The mechanical properties and sensory performance can be conveniently manipulated by designing the network structures of hydrogels to meet the demands of diverse applications. Linear sensitivity, wide working range, linearity, low limit of detection and stability are pursued by designing not only the network structure, but also the device configurations and microstructures. Moreover, the device-tissue interface is critical for implantable applications for monitoring the motions and health of tissues and organs. This review article systematically accounts the latest progress in the field of hydrogel sensors including our studies on tough conductive hydrogel sensors, paying special attention to structure-performance relationship, hydrogel-tissue adhesion, and application for human organ motion monitoring. Interpenetrating conductive/hydrophilic networks provide not only high strength and toughness, but also low percolation conductivity, high conductivity and linear sensitivity over a broad working range. Ion conductive hydrogels based on zwitterionic polymers show very high stretchability and ion conductivity, self-healing, and sensitivity, primarily attributed to the dipole-dipole interaction and ion conduction channels. Such zwitterionic sensors are adhesive to biotissues, and enable real-time monitoring of organ motions. The critical review aims to inspire new ideas to develop novel high performance hydrogel sensors, shed new insights into mechanisms behind the sensory performances, and boost hydrogel devices toward practical applications. Major challenges and future opportunities in this rapidly developing field are outlooked.
[Abstract](11) [FullText HTML](10) x[PDF 5637KB](0)
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Aliphatic diol HO-(CH2)6-S-S-(CH2)6-OH (DSU) containing disulfide bond was synthesized by the nucleophilic substitution reaction of halohydrocarbon, which was introduced into polyurethane molecules in the form of hard segment. A series of polyurethane composites modified by disulfide bond were prepared by using methylene diphenyl diisocyanate (MDI), dopamine modified castor oil and DSU as raw materials, and their structures and properties were optimized. The chemical structure of DSU was characterized by NMR, and the influence of the amount of DSU on polyurethane were investigated, including the compressive mechanical properties, water contact angle, microstructure and bone bonding strength. The main conclusions include that the compressive properties and hydrophobicity of polyurethane composites increased with the increase of DSU dosage, and the bone adhesion strength increased first and then decreased. As the DSU content increased to 10 wt.% of modified castor oil, the composites presented the best comprehensive properties with the bone adhesion strength of 0.97 MPa in the buffer solution and 0.49 MPa in rabbit blood, compression strength of 7.0 MPa, compression modulus of 41.2 MPa and average bubble size of 150 μm. In vitro culture experiments of rat bone marrow mesenchymal stem cells showed that the polyurethane composites had excellent cytocompatibility. The cell staining results by Calcein-AM showed that the porous structure of the material was conducive to cell proliferation and adhesion, which was in favour of fracture healing and reconstruction. This new material prepared in this work is expected to be used in the field of medical bone adhesives.
[Abstract](21) [FullText HTML](17) x[PDF 5157KB](5)
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In this study, we design and synthesize a series of β-amino acid polymers that have synergistic antifungal activity with itraconazole. The random copolymers DAP:Bu were obtained by ring-opening polymerization of β-amino acid N-thiocarboxyanhydrides (β-NTA) under room temperature using 4-tert-Butylbenzylamine (tBuBz-NH2) as an initiator, with DL-β-norleucine N-thiocarboxyanhydrides (β-Bu NTA) as hydrophobic monomer and N(α)-Z-DL-2,3-diaminopropionic acid N-thiocarboxyanhydrides (β-DAP NTA) as cationic monomer. The effect of DAP:Bu combined with itraconazole on C. albicans was evaluated by checkerboard antifungal test. The test showed that DAP:Bu copolymers could effectively reverse itraconazole resistance in C. albicans through synergistic effect, while the minimum inhibitory concentration (MIC) of antifungal of itraconazole was reduced from >200 μg/mL to 3.1 μg/mL after exposure to DAP:Bu, indicating that the antifungal activity of itraconazole reversed from ineffective to highly effective. In addition, most of DAP:Bu copolymers did not cause significant hemolysis of human red blood cells and fibroblasts toxicity at a high concentration of 400 μg/mL. Our studies demonstrate that the DAP:Bu copolymers can achieve efficient synergistic effect with itraconazole and reverse itraconazole resistance in C. albicans, showing broad potential in the treatment of fungal infections.
[Abstract](29) [FullText HTML](12) x[PDF 6083KB](2)
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The precisely-defined sequence structure of biomacromolecule, e.g., protein and DNA, enable the sophisticated and unique functions. Inspired by this, polymer scientists have made enormous efforts to achieve the precise sequence regulation in synthetic polymers. Up to date, a variety of approaches toward efficient sequence-regulation based on step-growth and chain-growth polymerization have been developed. This review summarizes the recent progress on the sequence regulation approaches, and highlights the latent monomer strategy for sequence regulation. The latent monomer strategy for sequence regulation developed by our group relies on the thermal-responsive furan/maleimide Diels-Alder reaction. By programmatically manipulation of the polymerization temperature, varieties of sequence-controlled structures are readily produced. Moreover, this approach also bridges from sequence-controlled polymers to graft copolymers with functions and architectures. Finally, a critical outlook on the latent monomer strategy and future research directions are also provided.
[Abstract](24) [FullText HTML](15) x[PDF 6050KB](2)
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Zirconium-ferrocene-based metal-organic framework (Zr-Fc MOF) with photothermal activities was loaded into soluble microneedle matrix composed of polyvinyl alcohol/ polyvinylpyrrolidone (PVA/PVP) to construct a microneedle (Zr-Fc MOF@MN) for photothermal antibacterial therapy. Zr-Fc MOF nanosheets were synthesized by bottom-up hydrothermal method. The structure and morphology of the Zr-Fc MOF nanosheets were characterized by X-ray diffraction, fourier transform infrared spectroscopy and scanning electron microscopy. Then, the photothermal and antibacterial properties of Zr-Fc MOF nanosheets were studied by infrared thermal imager and plate counting method. Zr-Fc MOF@MN was further prepared by template method, and the solubility and antibacterial properties of the microneedle patch were characterized. The results showed that Zr-Fc MOF nanosheet possessed good photothermal performance, and the temperature of Zr-Fc MOF (0.4 mg/mL) could rise to 57.4 °C after 10 min irradiation with 2.6 W/cm2 near-infrared light (808 nm). The results of antibacterial experiments showed that Zr-Fc MOF (0.4 mg/mL) could kill about 100% bacteria under 2.6 W/cm2 of near-infrared light irradiation for 10 min. The prepared Zr-Fc MOF@MN could be dissolved in water, which showed almost 100% photothermal bactericidal properties and low hemolysis rates.
[Abstract](68) [FullText HTML](19) x[PDF 5249KB](14)
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Cellulose nanocrystals are a kind of sustainable nanoparticles from biomass, which are expected to be widely used in the fields of composite reinforcement and functionalization due to its highly controllable mechanical property and surface properties. Furthermore, their intrinsic rod-like morphology and orderly crystal structure have great advantages in the sensors and anti-counterfeiting of chiral and oriented array assembly optics. In this review, we described their unique advantages in material applications due to their rod-like morphology and crystalline structure of biocompatible nanoparticles, as well as their dimension-related effects and multi-level structure. Notably, controlling the surface structure and physicochemical property of cellulose nanocrystal played the key role in developing related high-performance and multi-function materials. Thus, we focused on the mechanism and methods of controlling the surface structure and properties of cellulose nanocrystal, along with its steric and spatial dimension effect. The chemical regulation strategies covered the changes in interaction mode, degree of system interface interaction, network structure and percolation behavior. We further discussed the performance-improvement and functionalization methods based on controlling the interactions between materials in the multicomponent complex phase/system, along with the assembly-control methods on the chiral and achiral array of CNC for luminescence-enhanced optical anti-counterfeiting. It included the adjusting mechanisms and optimization methods of the micro-environment structure and field effects. In the end, we prospected the design, development, and construction methods of new CNC materials, as an important way and application expansion to provide a theoretical guidance and practical reference for the application basic research of natural polymer modified materials and the construction of high-performance multifunctional materials.
Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes /issues, but are citable by Digital Object Identifier (DOI).
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[Abstract](13) [FullText HTML](8) [PDF 5390KB](2)
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Hypercrosslinked polymer (HCP) is a class of microporous organic polymer connected by light elements (C, H, O and N) through covalent bonds. In order to efficiently adsorb soluble organic dyes in water treatment, here, an ionic HCP (HCP―SO3Na) was prepared through an efficient Friedel-Crafts reaction from sodium 4-(phenylamino)benzenesulfonate and benzene in the presence of formaldehyde dimethyl acetal and anhydrous FeCl3. A series of characterizing techniques such as elemental analysis, infrared spectroscopy, N2 adsorption-desorption analysis, solid-state 13C nuclear magnetic resonance spectroscopy and thermogravimetric analysis were employed to characterize the structure and thermal property of the ionic polymer. It was found that HCP―SO3Na was an amorphous microporous polymer with large specific surface area and high thermostability. The specific surface area and micropore area were 587 and 411 m2/g respectively. The adsorption of HCP―SO3Na for the organic dye of rhodamine B demonstrated the ―SO3Na groups distributing uniformly in the polymer can increase the saturation capacity of HCP. The maximum adsorption capacity was up to 431 mg/g. The adsorption process conformed to kinetic pseudo-second-order model and Langmuir model. HCP―SO3Na can be easily recovered and reused five times without significant loss of activity.
[Abstract](27) [FullText HTML](34) [PDF 7687KB](95)
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[Abstract](75) [FullText HTML](46) [PDF 5557KB](17)
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Polypyrrole (PPy) is a photothermal conversion material with high efficiency and broad-spectrum absorption of sunlight. Polypyrrole chitosan (PPyCS) composite aerogel was prepared by freeze drying and applied to the solar water evaporation system. The preparation process of polypyrrole was optimized by controlling the crosslinking degree of aerogels and the polymerization time of polypyrrole. Results showed that the excellent photothermal conversion performance of PPy made the PPyCS composite aerogels with high absorbance (97.83%). Under the light intensity of 1 kW/m2, the crosslinking agent (glutaraldehyde) was 150 μL, and polypyrrole reacted for 3 h, the composite aerogels achieved the best value. The evaporation rate 2.6 kg/ (m2·h) and the photothermal conversion efficiency was 97.63%. Under the light intensity of 1 kW/m2, the composite aerogel had higher evaporation rate (1.129 kg/(m2·h)) for natural seawater. After the 5 repeated tests, the photothermal conversion efficiency of the composite aerogel basically remained the same for the simulated seawater desalinated with 1 000 mg/L concentration. The water quality after treatment reached World Health Organization (WHO) drinking water standard.
[Abstract](327) [FullText HTML](143) [PDF 5816KB](28)
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I Inspired by natural healing processes, a variety of synthetic self-healing materials have been developed, including fiber reinforced polymer (FRP) composites. Therefore, self-healing FRP composites have recently become a focus in the fields. This paper considers the development of autonomic self-healing within a glass fiber-reinforced polymer (GFRP). Vascularised GFRP was prepared from glass fiber SW280A reinforced epoxy 3218 by removing Nylon fibers after curing. A homemade ambient-curable healing resin formation (diglycidyl ether of bisphenol-A/aliphatic amine) epoxy system has been used as a self-healing agent. It was demonstrated that the post-impact compression strength recovery of the self-healing GFRP by ultrasonic C scan, micro-X-ray computer tomography (μ-CT). In this study, a autonomous, stimulus triggered, self-healing system in GFRP composites was established. Vascules are used as sensing pathway, which detect the introduction of ply delaminations and matrix microcracking following from 6.67 J to 10 J low-velocity impact events. Once damage connectivity between the sensing vascules and those open to the ambient environment is established, the delivery of a healing agent to the damage zone is triggered. Two kinds of samples with vascules orientation of parallel and transverse to the 0°was prepared. In both samples, the damage was connected with the vascules following from low-velocity impact events. The healing agents flowed into damage position and the sample can be healed. Using this autonomous healing approach, near full recovery of post-impact compression strength (211 MPa) was achieved compared with compression after impact (202 MPa). The successful implementation of this bioinspired technology could substantially enhance the integrity and reliability of aerospace structures, which offering benefits through improved performance/weight ratios and extended lifetimes.
[Abstract](126) [FullText HTML](77) [PDF 5482KB](86)
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Biological tissues including muscles, cartilage and other human tissues have excellent mechanical anisotropy and electrical anisotropy due to their reasonable arrangement of microstructures. The anisotropic hydrogel has excellent function due to its ordered orientation structure, which shows great application prospects in biomimetic muscles, actuators, drug delivery, and flexible sensing. However, the methods to prepare anisotropic hydrogels are limited. Inspired by the anisotropic structure from nature products, we proposed a strategy to build anisotropic hydrogel based on plant skeleton. First, we observed and searched for anisotropic structures among diverse vegetables, and pre-treated them to obtain anisotropic skeleton. Furthermore, the cross-linking of polyacrylamide (PAM) within the anisotropic skeleton was in-situ initiated, resulting in a hybrid anisotropic hydrogel. The anisotropic hydrogel with plant skeleton and PAM hydrogel could be successfully constructed. A highly anisotropy in structure and mechanical property could be achieved. This work obtained a highly anisotropic hydrogel with a feasible method, and we hoped to shed new lights for a novel anisotropic hydrogel construction.
[Abstract](379) [FullText HTML](213) [PDF 6044KB](51)
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Polydimethylsiloxane (PDMS) has good thermal stability, biocompatibility and corrosion resistance, and it has been widely used in the field of biomedical materials, i.e., medical catheters. However, the surface of PDMS is highly hydrophobic and susceptible to contamination by bacteria and plasma proteins. In this study, PDMS-TA-Ply surfaces were prepared by the rapid and successive deposition of tannic acid (TA) and ε-poly-L-lysine (Ply) on the PDMS surface via the solution immersion method. The surface chemical elements and hydrophilic properties of PDMS-TA-Ply surfaces were evaluated by X-ray photoelectron spectroscopy (XPS) and contact angle measurement. The anti-protein adsorption, antibacterial adhesion, anti-biofilm formation and cytotoxicity of PDMS-TA-Ply surfaces were evaluated. The results showed that PDMS-TA-Ply surfaces exhibited good antibacterial properties and low cytotoxicity toward L929 mouse fibroblasts. In addition, the PDMS-TA-Ply surface with higher content of Ply showed better antifouling/antibacterial performance.
[Abstract](267) [FullText HTML](156) [PDF 5873KB](17)
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Degradable magnetic and CO2 dual-responsive microgels were prepared by inverse suspension polymerization and in-situ synthesis of nanoparticles. The structure and morphology of microgels were characterized by Fourier-transformed infrared (FT-IR) spectroscopy, scanning electron microscope (SEM) and transmission electron microscope (TEM). The microgels exhibited magnetic and CO2 responsiveness, and could be degraded upon the treatment of D, L-dithiothreitol (DTT). After treating with the stimulus of CO2, the microgels exhibited a selective adsorption for anionic dyes. The maximum adsorption capacity was up to 1413 mg/g for Alizarin red (AR). The microgels with adsorbates could be separated from solutions under the help of an external magnetic field. Besides, the adsorbates could be described by treating with solution of pH 12. Microgels regenerated with CO2 trigger exhibited high adsorption ability (>90%) after three consecutive recycling trials.
[Abstract](347) [FullText HTML](171) [PDF 5627KB](57)
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Premature leakage of drugs into the bloodstream remains a problem in the process of drug delivery, resulting in higher toxic and side effects on normal tissue cells. Novel drug carriers enabling effective drug accumulation in the tumor site have got much attention of researchers. Poly (methyl acrylic acid diisopropyl amino ethyl ester) (PDPA) is a polymer with pH-sensitive response, the diisopropylamine in the side chains are protonated in an acidic environment, resulting in its changing from hydrophobic to hydrophilic. PDPA was grafted onto the surface of mesoporous silica nanoparticles (MSNs) by atom transfer radical polymerization (ATRP) reaction. Then folic acid (FA) was introduced onto PDPA as a targeting ligand for enabling the drug carrier to enter tumor cells effectively. Simultaneously poly [di (ethylene glycol) methyl ether methacrylate-co-oligo (ethylene glycol) methacrylate]-b-poly[methyl acrylic acid diisopropyl amino ethyl ester] (P(MEO2MA90-co-OEGMA10)-b-PDPA10) with dual sensitivity of temperature and pH was synthesized and the lower critical solution temperatures (LCST) of the polymer was adjusted to 44 ℃ by adjusting the proportion of three monomers. A drug carrier with a core-shell structure was self-assembled through hydrophobic force by covering the later polymer on the surface of MSNs-PDPA-FA. Finally, the drug release kinetics of the carrier was studied by using doxorubicin(DOX) as a model drug, and the result showed that the total leakage of the model drug DOX was less than 10% after 48 h in normal physiological environment (pH=7.4, 37 ℃). However, when the pH value was changed to 5.0 at 44 ℃, the shell was dissociated from the core and the drug was released. Then, the drug was released rapidly within 5 h and the cumulative drug release could reach to 65% in 48 h. Therefore, this research was expected to construct a shielding system based on the pH/temperature dual-responsive polymer, which could be used to avoid premature exposure of certain functional groups or molecules to the normal physiological environment, and it could also prevent the premature release of drugs in the normal tissues.
[Abstract](262) [FullText HTML](138) [PDF 5945KB](69)
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Graphene oxide (GO) with different lateral sizes was doped into the shape memory capable fibrous membranes of poly(L-lactic acid)/poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PLLA/PHBV) composite via electrospinning. A series of characterizing techniques such as Raman spectroscopy (Raman), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were employed to characterize the structure and thermal properties of the fibrous composite membranes. Thereafter, shape memory properties were determined by dynamic mechanical analysis (DMA), shape recovery stress, and photothermal effect test. Finally, the effect of GO lateral sizes on the osteodifferentiation capacity of bone mesenchymal stem cells (BMSCs) cultured on the fibrous composite membranes was examined by conducting cell proliferation and osteodifferentiation relevant assays. It was found that incorporation of small-sized GO (sGO) into the fibrous composite membranes gave rise to the most significant reinforcing effects on the mechanical strengthening and shape recovery capability of the fibrous PLLA/PHBV membranes, with the tensile Young's modulus increased by about 124%, the shape recovery stress increased by about 29%, the shape recovery rate increased by about 47%, and the thermal responsive rate increased by about 30 fold. In terms of osteogenic performance, the fibrous PLLA/PHBV membranes doped with large-sized GO (lGO) demonstrated the best osteogenic induction capacity in BMSCs, with the secreted alkaline phosphatase (ALP) increased by 92% and the calcium deposits by 133%.
[Abstract](70) [FullText HTML](45) [PDF 6046KB](14)
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: Poly(L-lactide) (PLLA) and polybutyrolactam (PBL) are both biocompatible and biodegradable polymers. Here, bio-based and biodegradable fibers were electrospun from PLLA/PBL blend solutions dissolved in hexafluoroisopropanol (HFIP), the co-solvent of PLLA and PBL. The influences of PBL mass fraction on fiber properties including morphology, average diameter, thermal, crystallization and hydrophilicity properties were investigated by scanning electron microscope (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and contact angle testing. The internal structure of blend fibers was confirmed by transmission electron microscope (TEM). Dichloromethane (DCM) , the solvent of PLLA was used to etch the fibers to give a supplementary proof. It was found that beads free homogeneous fibers without band structure could be obtained from PLLA/PBL blends. The diameters of fibers distributed in a range of 0.1~1.6 μm. The average diameters of PLLA/PBL blend fibers were lower than those of pure PLLA fibers and decreased with the increasing of PBL mass fraction. The crystallinity of PLLA in as-spun fibers was low, and it could be increased by cooling from 190 °C that above the melting point of PLLA or annealing at 110 °C above its glass transition temperature. Introducing PBL into PLLA fibers hindered the melt and annealed crystallization of PLLA. The reduction in the degree of PLLA crystal perfection was characterized by the obvious decrease in either PLLA crystallization temperature during cooling or the melting temperature in the second heating. The broadening of the half-peak width of PLLA crystal diffraction peaks was another evidence provided by XRD. All evidences from TEM observation and solvent etching experiment suggested that the fibers with core-sheath structures were obtained by single-nozzle electrospinning from solutions of PLLA/PBL blends. The phase separation occurred during the electrospinning process due to various segment mobility should be responsible for the fiber structure with PBL core and PLLA sheath. It could explain why the addition of hydrophilic PBL hardly improved the hydrophilicity of as-spun fiber surfaces.
[Abstract](123) [FullText HTML](143) [PDF 5491KB](86)
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Self-assembly of copolymer micelles has become an appealing frontier of supramolecular chemistry as a strategy to construct superstructures with multiple levels. However, how to reveal the universal law and solution behavior of the hierarchical self-assembly process is a profound issue to be explored. Supramolecular polymerization of nanoscale particles has been considered as an effective route to prepare hierarchical nanostructures. The micelles self-assembled from poly (γ-benzyl L-glutamate)-g-polyethylene glycol (PBLG-g-PEG) can further assemble into hierarchical nanowires under low-temperature conditions. The static light scattering (SLS) characterization can extract the kinetic and structural information of copolymers in solution comprehensively and effectively. The spindlelike subunits with structural defects at both ends were prepared from PBLG-g-PEG graft copolymers. To obtain the structure information of nanowires in solution, the SLS characterization and dissipative particle dynamics (DPD) simulation were combined to study and analyze the state of hierarchical nanowires in solution. The effects of initial mixed solvent and growth time on nanowires were further discussed. Results show that the dependence of the shape factor on scattering wave vectors is closely related to the length scale, which reveals the structure of nanowires with various degrees of polymerization. The formed nanowires exhibit polydispersity characteristics and certain flexibility. The nanowires formed by hierarchical self-assembly can be comparable with copolymers, which shows the characteristics of rigid polymers, which are closely related to the ordered arrangement of the PBLG chain. The research work clarifies the state of hierarchical nanowires in solutions and provides a means for analyzing assembly structure in solutions.
[Abstract](72) [FullText HTML](160) [PDF 5364KB](11)
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Polymeric nanotubes have great advantages in biological carrier applications due to their flexible structure design and large aspect ratio. The independence of self-assembly structure from molecular weight and molecular weight distribution is a major advantage of alternating polymers for self-assembly. In the present study, a series of amphipathic alternating copolymers with hydrophobic sections of different lengths by thiol-halogen click chemistry reactions are synthesized. The molecular weight and structure of three alternating copolymers are characterized by gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR). These alternating copolymers self-assemble in water and dimethyl sulfoxide (DMSO) (volume ratio 4∶1) and form a series of ultrathin nanotubes with a wall thickness of only 1—2 nm. Through transmission electron microscope (TEM), it could be observed that as the length of the carbon chains in the hydrophobic sections of the alternating copolymers increases, the diameters of the nanotubes increase from 19.61 nm to 26.24 nm. Besides, through the software simulation of Chem3D, the hypothesis is verified that the alternating copolymer folds to form a sandwich structure and further self-assembles into nanotubes. The nanosheets assembled by alternating copolymers with longer hydrophobic sections are thicker, the bigger bending stress resulting in the formation of larger diameter nanotubes which are more thermodynamically stable. Biological carriers need on-demand release when they reach the target. Therefore, the carriers generally required to have the ability to controllable release or disintegrate. In this study, the hydrophobic thioether bonds in alternating copolymers are transformed to the sulfone bonds after oxidation. The better water solubility of sulfone bonds will enhance the hydrophilicity of the alternating copolymers, which caused the tubular structure of the nanotube to decompose after oxidation by H2O2 at 37 °C for 2 h. The large aspect ratio and controlled degradation of these nanotubes may have potential applications in biological delivery and controlled releasing.
[Abstract](251) [FullText HTML](121) [PDF 5152KB](23)
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Azobenzene has two configurations which are trans-configuration and cis-configuration. As a photo-isomerization molecule, azobenzene can transfer from trans-configuration in low energy state to cis-configuration in a high energy state under the irradiation of ultraviolet light (UV), which is the process of photo-isomerization. Herein, azobenzene and its derivatives are used in different industries and fields. However, due to their low energy density compared with other molecular solar thermal energy storage (MOST) like anthracene and norbornadiene, their applications in energy storage are influenced severely. The purpose of this paper is to find a method to solve the problem above. In this paper, 4-nitro-4'- aminoazobenzene (Azo) was grafted onto reduced graphene oxide (rGO) by the coupling reaction and then interacted with ZnCl2 to get the azobenzene graphene composite with zinc ion interaction (AGO/Zn). There are two mechanisms of energy storage/release in this method, photoisomerization of azobenzene onto graphene template, and ion interaction formation/destruction, which is a unique attempt to improve energy density through multiple mechanisms of heat release. It has been proved that the nanoscale templates have a significant effect on improving the energy density of azobenzene derivatives. FT-IR spectroscopy show that AGO/Zn is successfully prepared by this method. Moreover, the maximum energy density of that is up to 504.2 J/g under the irradiation of UV (365 nm) for 4 h, which is about 1.69 times of the azobenzene graphene composite (AGO) without ion interaction. Results show that the introduction of zinc and graphene templates greatly improves the energy density of azobenzene, which provides a reference for the development and application of azobenzene composites with multiple mechanisms of energy storage in the future.
[Abstract](90) [FullText HTML](60) [PDF 5683KB](20)
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When polymers are in blends or used together, the ageing process of polymer components or polymers affects each other, which is called infection behavior of ageing. Due to the infection behavior during ageing of polymer, the research results of an individual polymer cannot be used to predict the life of this polymer material in blends or being used with other polymers. Therefore, infection behavior is an important topic in the field of ageing study. This article mainly features the research progress towards infection behavior of polymer ageing. Firstly, the "contacting" and "non-contacting" behaviors are emphatically illustrated, which are the two typical patterns of infection behavior of ageing. Ageing spreads via infection agents within a polymer or polymer blend, and between different polymers separated from each other. Infection agents play an important role in infection behavior. Then, the source and effects of infection agents are analyzed. Infection agents include radicals, volatile organic small molecules, gases, volatile additives and so on. All these infection agents work in "contacting" behavior, while volatile and gaseous matter are more important in "non-contacting" behavior. Benzoyl peroxide (BPO), formaldehyde and acetic acid are found to accelerate the thermo-oxidative ageing of polypropylene (PP). Eighteen volatile organic small molecules including acids, esters, aldehydes, ketones and alcohols are demonstrated to accelerate the photo-oxidative ageing of PP to different extents. Finally, the applications of infection behavior in the field of environmental protection and heritage protection are introduced and the challenges and prospects are proposed. The characterization of infection agents and their mechanism of action remain to be clarified systematically.
[Abstract](118) [FullText HTML](80) [PDF 5484KB](60)
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A colorless and transparent polyimide (PI) film with excellent comprehensive properties was synthesized via chemical imidization process by using 4,4'-diaminodiphenyl ether (ODA) and 9,9-bis(3-fluoro-4-aminophenyl)fluorene (FFDA) as diamine monomers, 4,4'-oxydiphthalic anhydride (ODPA) as dianhydride monomer in dimethylformamide (DMF). The relationship between the content of FFDA and the performance of PI was studied. The optical properties, heat resistance, mechanical properties and solubilities of PI were characterized by ultraviolet-visible spectrophotometer (UV-Vis), differential scanning calorimeter (DSC), thermogravimetric analyzer (TGA), universal material testing machine, etc. The addition of diamine monomer with asymmetric large side group can increase the degree of distortion of the molecular chain to a certain extent, increase the free volume between molecules, reduce the stacking of molecular chains, and reduce the interaction among molecular chains, which weakening the charge transfer complexing effect and improving the optical transparency of the PI film. The addition of ether bonds can increase the flexibility of PI molecular chains and improve the solubility. The fluorine-containing group of the diamine part has a strong electron withdrawing effect, which significantly reduces the electron donating effect of the diamine monomer, thereby inhibiting the charge transfer complexing (CTC) effect and improving the optical performance of PI film. The results show that the PI sample with n(FFDA):n(ODPA)=50% exhibits excellent solubility and the film presents good optical property. At ambient temperature, the PI is soluble in many strong polar solvents such as N-methyl pyrrolidone (NMP), dimethyl formamide (DMF), dimethyl acetamide (DMAc) and dimethyl sulfoxide (DMSO), which also has good solubility in weak polar solvents such as tetrahydrofuran (THF). The transmittance of PI film at 500 nm attains 85%, and its UV cutoff wavelength is as low as 365 nm. Mean-while, the PI film has excellent thermal stability and mechanical properties.
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As a typical anode material for sodium-ion batteries, hard carbon has attracted much attention due to its high energy density and reproducibility. After a series of washing, drying, grinding and impurity removal, the sycamore husk-derived hard carbon was successfully prepared at different carbonization temperatures. Scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), Raman spectroscopy, and nitrogen absorption and desorption are used to study the effects of temperature on the surface morphology, phase structure and pore size distribution of the material. Results show that the increase of carbonization temperature can destroy the internal pore structure of hard carbon. After the carbonization process, the surface of hard carbon becomes smooth and dense, the specific surface area and the spacing of hard carbon layers decrease, but the long-range and short-range directions of graphite crystallites increase, which enhance the charge/discharge specific capacity and rate performance. When the carbonization temperature rises to 1000 °C, as an anode material for sodium ion storage, the biomass hard carbon has a relatively high reversible capacity (the first cycle discharge specific capacity reaches 400 mAh/g) and the first cycle coulombic efficiency (73%), ultra-stable cycling performance (capacity of 244 mAh/g after 100 cycles at 50 mA/g), and excellent rate capability (capacity of 120 mAh/g at 0.5 A/g), while sodium-ion diffusion can reach the level of 10−8 cm2/s. The preparation of sycamore husk-derived hard carbon provides a new solution for large-scale preparation of safe, low-cost, and high-performance anode materials for sodium-ion batteries.
[Abstract](21) [FullText HTML](6) [PDF 5948KB](3)
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Waterborne polyurethane (WPU) antibacterial film was prepared by UV curing after introducing hydrophilic quaternary ammonium salts via quaternization reaction between different alkyl chain haloalkanes and tertiary amine groups to polyurethane (PU) molecular chains. PU were bonded with tertiary amine group and unsaturated group, using 3-dimethylamino-1,2-propanediol as the chain extender and hydroxyethyl methacrylate as the capping agent. The structure and properties of WPU dispersion and light cured films were characterized by FT-IR, particle size analyzer, optical contact angle instrument, etc. The antibacterial properties of the materials were tested by shaking-flask method and zone of inhibition. And the effects of tertiary amine compounds on the properties of WPU was investigated. Results showed that when the mass fraction of tertiary amine compound was 9% and the alkyl long chain was 12, the antibacterial rates of WPU against Gram-negative E. coli and Gram-positive S. aureus were more than 99.5%, meanwhile the longer the alkyl chain, the better the effect. Through UV-curable crosslinking, it could still maintain excellent antibacterial performance and reflect positive durability after 96 h water washing. The zone of inhibition test shown that the prepared quaternary ammonium salts WPU antibacterial film belonged to contact-killing material which avoided the pollution and adverse effects on the environment, human beings and other materials. With the increase of tertiary amine content, the quaternization degree of WPU system first increased and then decreased, and the variation of quaternization degree affected the antibacterial properties. Moreover, polyurethane material also exhibited good mechanical properties. The increase of hard segment content of the system enhanced the tensile strength of polyurethane. And when the alkyl long chain was 12, the waterborne polyurethane material had better toughness.
[Abstract](19) [FullText HTML](20) [PDF 5444KB](2)
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Most of the traditional permanent hair dyes containing aniline molecules have the risk of carcinogenicity and sensitization. Since polydopamine has a similar molecular structure to eumelanin and good biocompatibility, the use of polydopamine in hair dyeing has become a hot research topic. However, due to the hydrophobic structure of the hair surface, the adhesion of dopamine in situ deposition on the hair surface is weak. Here, by taking advantage of the effect of hyaluronic acid (HA) to hair, dopamine (DA) was grafted onto HA via Schiff base reaction to strengthen the interactions between polydopamine and hair. The chemical structure of DA grafted hyaluronic acid (DAHA) was confirmed by Fourier Transform Infrared Spectrometer (FT-IR), Ultraviolet-Visible Spectrophotometer (UV) spectrophotometer, Proton Nuclear Magnetic Resonance (1H-NMR). The dyeing properties assisted by DAHA were characterized by Scanning Electron Microscope (SEM), single fiber strength tester and colorimeter. The results show that DA has been successfully grafted onto HA, and the grafting ratio for HA with a number average molecular weight of 0.2×104~1.0×104 was 34%. Compared with the hair samples dyeing without DAHA, the hair pretreated with DAHA has better color fastness after 30 washes. Moreover, with DAHA pretreatment, the tensile strength of hair improves, and the improvement rate is about 7.4%. SEM photos demonstrate that the polydopamine nanoparticles on the surface of hair dyed with DAHA were more uniform than those without DAHA.
[Abstract](31) [FullText HTML](17) [PDF 5249KB](8)
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In this contribution, the ring-opening copolymerization (ROP) of hexaethylcyclotrisiloxane (E3), and the ring-opening copolymerization E3 and 1,3,5-trimethyl-1,3,5-tri(3,3,3-trifluoropropyl) cyclotrisiloxane (F3) was catalyzed by organic cyclotrisiloxane base (CTPB) under mild conditions. CTPB showed high catalytic activity for the polymerization of E3 and F3. Linear polydiethylsiloxanes (PDES) and poly(diethyl-ran-trifluoropropyl methyl) siloxanes (PDES-ran-PTFPMS) with different trifluoropropyl methyl siloxane group (F) (mole fractions: 0～46%) were successfully synthesized. The composition and structure of the PDES-ran-PTFPMS copolysiloxanes were characterized in detail by gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR), and the glass transition temperature (Tg) and crystallization behavior of the polymers were comprehensively analyzed by differential scanning calorimetry, and the water-oil contact angle of fluorine-containing polyethylsiloxane film was investigated by microscopic contact angle test. The chemical positions of the resonance peaks in the nuclear magnetic resonance spectrum (1H-NMR and 29Si-NMR) were analyzed, indicating that the PDES-ran-PTFPMS copolysiloxanes was successfully prepared. The results of differential scanning calorimeter (DSC) indicated that the crystallization of polydiethylsiloxane at low temperature can be entirely inhibited by the introduction of tri(3,3,3-trifluoropropyl)-methyl siloxane groups. The obtained PDES-ran-PTFPMS copolysiloxanes has a low glass transition temperature Tg (−134 ºC), has very excellent low temperature performance, and is an ideal precursor material for low temperature resistant rubber materials. When the contents of the methyl-tri(3,3,3-trifluoropropyl)siloxane group are higher than 6.0%, the crystallization behavior was inhibited. The results of contact angle test of fluorine-containing polyethylsiloxane film demonstrated that the introduction of tri(3,3,3-trifluoropropyl)-methyl siloxane groups into the PDES chain can effectively improve its hydrophobicity and decrease the oil wettability.
[Abstract](12) [FullText HTML](4) [PDF 5330KB](1)
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Poly (aryl ether sulfone) with chloromethylation rate of 150% (CMPSF150) was synthesized, and then CMPSF150 was reacted with p-hydroxybenzyl alcohol to synthesize side-chain poly (aryl ether sulfone) (PSF-HBA150). Side chain chloromethylated poly (aryl ether sulfone) (PSF-CM150) was synthesized by reaction of PSF-HBA150 with thionyl chloride. PSF-CM150 was quaternized with piperidine and alkalized to prepare side-chain piperidine-functionalized poly (aryl ether sulfone) anion exchange membrane (QPSF-Pip150). Finally, crosslinked anion exchange membrane with different crosslink degree (cQPSF-Pipx-TAPy, x was the mole percentage of functional cation, y was the mole percentage of 2,4,6-tris(dimethylaminomethyl) phenol (TAP)) were prepared by controlling the ratio of the crosslinking agent TAP to piperidine. The polymer structure was characterized by 1H-NMR. cQPSF-Pipx-TAPy were insoluble in any solvent, the initial decomposition temperature and tensile strength of cQPSF-Pipx-TAPy increased up to 18 °C and 14.7 MPa higher than QPSF-Pip150, respectively. QPSF-Pip150 was completely damaged after soaking in distilled water at 80 °C for 48 h, but cQPSF-Pipx-TAPy were intact. The water absorption rates of cQPSF-Pip130-TAP20 and cQPSF-Pip120-TAP30 were 87.4% and 72.5%, the swelling rates of cQPSF-Pip130-TAP20 and cQPSF-Pip120-TAP30 were only 19.7% and 16.4%, respectively. The ionic conductivity of cQPSF-Pip130-TAP20 was up to 131.5 mS/cm at 80 °C, while the swelling rate is only 19.7%. Ion exchange capacity and ionic conductivity of cQPSF-Pip130-TAP20 and cQPSF-Pip120-TAP30 still remain 81.7%—91.1% and 73.1%—85.9% after soaking in 1 mol/L NaOH at 60 °C for 20 d, respectively. The mechanical properties, thermal stability, dimensional stability and alkaline stability of anion exchange membranes were effectively improved by crosslinking.
[Abstract](23) [FullText HTML](17) [PDF 6453KB](2)
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Inspired by the dynamic properties of hindered urea bonds (HUBs), prepolymer of polyurethane-acrylate (PUA) with HUBs was designed and synthesized using 1,3-bis(2-isocyanato-2-propyl)benzene (TMXDI) as hard segment, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate (TMPCA) as soft segment, isobornyl methacrylate (IBOMA) as reactive diluent, and 2-hydroxyethyl methacrylate (HEMA) as block agent. The prepolymer was subsequently UV-cured to obtain PUA photopolymer. The property and reaction mechanism of the incorporated dynamic HUBs were investigated via Differential Scanning Microcalorimetry (MicroDSC) and Fourier Transform Infrared (FT-IR) spectroscopy. And studies were carried out in terms of the repairability, shape memory and reshapability of the corresponding photopolymer. Results showed that the thermal effect of the HUB could be identified in MicroDSC analysis, as an endothermic peak appeared in the range of 46 °C to 56 °C. In addition, the dynamic content variation of the isocyanate group (NCO) could be observed via temperature-dependent FT-IR in both prepolymer and cured resins. In the in-situ FT-IR spectra of prepolymer with HUBs, the characteristic peak of NCO was observed to increase when heated from 30 °C to 80 °C, which later decreased when cooled down to 30 °C. Also, the peak area of NCO characteristic peak increased in cured resins with increased temperature. The dynamic nature of HUBs allowed the obtained photopolymer to be repaired with a demonstrated improvement in mechanical properties. By drilling a 1 mm hole in the center of a testing sample, refilling prepolymer, and treating with UV-cure and post-cure, the tensile strength of the material was observed to recover from 13.8 MPa to 18.4 MPa after repairing. Meanwhile, the repair interface width was less than 50 μm. Also, the incorporated HUBs provided the PUA resin with shape memory and reshaping capacities, and the testing sample was able to reserve a 45 MPa flexural strength after being reshaped.
[Abstract](65) [FullText HTML](42) [PDF 5578KB](81)
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Water-soluble polyurethane was synthesized by using polyether polyol and diisocyanate as the main raw materials, small molecule diol and methyl pyrrolidone as auxiliary raw materials, and N-methyl diethanolamine (MDEA) as a hydrophilic chain extender, and the synthesized polyurethane was coated on continuous basalt fibers as a film-forming agent. The properties of water-soluble polyurethane and continuous basalt fibers were studied. The most suitable water-soluble polyurethane was selected as the film-forming agent for the infiltrate. Water contact angle tester, laser particle size analyzer and thermal weight loss analysis were used to study the storage stability, water contact angle, particle size and thermodynamic properties of water-soluble polyurethanes. Fourier infrared spectroscopy, universal testing machine and scanning electron microscopy were used to characterize the chemical elemental composition of continuous basalt fiber surfaces before and after polyurethane treatment. Mechanical properties and surface morphology were also investigated. The continuous basalt fibers before and after the infiltrate treatment were also subjected to acid and alkali treatment to observe the fracture strength retention and mass retention of the fibers. Results showed that when the mass fraction of MDEA (w(MDEA)) was 6.0%, the waterborne polyurethane had good stability, uniform particle size distribution and ideal water resistance. The fracture strength of continuous basalt fibers treated with sizing agent was increased by 175%, and the toughness was similarly improved. After acid-base treatment, the fiber breaking strength retention and quality retention were significantly increased.
[Abstract](137) [FullText HTML](70) [PDF 5299KB](94)
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Epoxy resin is widely used in coatings and adhesives for its excellent mechanical performance, heat resistance and bonding property. Thiol-epoxy “click” reaction has become one of the hotspots in the field of photocuring due to its mild and efficient reaction conditions. As a latent photoinitiator, the photobase generator improves the storage stability of the formulation when it catalyzes the thiol-epoxy reaction. However, due to the low dose rate and poor solubility of the photobase generator, thiol-epoxy reaction rate is slow under light conditions. To solve this problem, a novel kind of near infrared (NIR) light induced thiol-epoxy photopolymerization system was established in this paper using the up-conversion particles (UCPs) as upconversion material, 980 nm NIR light as irradiation source. The up-conversion material assisted near infrared photopolymerization (UCAP) technology was used to study the NIR light-induced thiol-epoxy step photopolymerization, and the effect of photothermal synergistic effect of NIR light on thiol-epoxy reaction catalyzed by photobase generator was explored. The temperature change of the polymerization system was measured by infrared thermal imager, the reaction rate of sulfhydryl group and epoxy group under NIR irradiation was measured by real-time infrared, and the molecular weight of the polymer was measured by gel permeation chromatography (GPC). Results show that under the irradiation of NIR light (980 nm), the photobase generator absorbs the light emitted by the UCPs to generate a strong base which catalyze the step photopolymerization of thiol and epoxy monomers. Under the photothermal synergistic effect of NIR, the typical step polymerization of thiol-epoxy system catalyzed by photobase generator takes place. Kinetics and molecular weight studies show that the polymerization exhibits typical step growth characteristics, and proves the time controllability of the polymerization. The results are expected to promote the application innovation of photoalkali-producing material system in the fields of photocuring 3D printing and adhesives.
[Abstract](26) [FullText HTML](8) [PDF 5658KB](7)
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Aimed to rapidly form high-quality cell sheets, poly(N-isopropylacrylamide-co-acrylic acid) (PNIPA-AA) was synthesized by free radical polymerization of N-isopropylacrylamide (NIPA) and acrylic acid (AA). Chemical structure of the synthesized PNIPA-AA was characterized by nuclear magnetic resonance spectroscopy (NMR) and Fourier infrared spectroscopy (FT-IR), and temperature sensitivity was detected by variable temperature infrared spectroscopy and ultraviolet-visible spectrophotometry. PNIPA-AA was subsequently blended with polycaprolactone (PCL) for electrospinning thermosensitive fibrous substrate of PNIPA-AA/PCL. Morphology of the electrospun fibrous PNIPA-AA/PCL substrate was observed by scanning electron microscopy (SEM) and its temperature sensitivity was confirmed through water contact angle measurement. Using mouse fibroblasts C3H/10T1/2 as model cells, effects of the fibrous PNIPA-AA/PCL substrate on the formation and detachment of cell sheets were examined. Results showed that the lower critical solution temperature (LCST) of PNIPA-AA was 33.6 °C. PNIPA-AA possessed better electrospinnability. Electrospun fibrous substrate of the PNIPA-AA/PCL showed higher hydrophobicity at high temperature (37 °C) and faster water infiltration rate at low temperature (20 °C). The fibrous PNIPA-AA/PCL substrate promoted cell proliferation and extracellular matrix (ECM) secretion in C3H/10T1/2. Moreover, it took merely 10 minutes for the formed cell sheets to be completely detached by cooling down the temperature to lower than LCST, e.g., 20 °C. And the integrity and function of the harvested cell sheets remained intact.
[Abstract](81) [FullText HTML](21) [PDF 6187KB](20)
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Ionic conductive hydrogels exhibit good electrical conductivity, excellent tensile properties and high biocompatibility, which is of great significance in the fields of flexible electronic equipment, human-machine interface and health monitoring. By using acrylamide (AAm) monomer and methyl acryloxyethyl trimethylammonium chloride cationic monomer (DMC) as copolymers and adding a certain amount of anionic polyelectrolyte sodium polyacrylate (PAAS), ionic conductive hydrogels with hybrid crosslinking network(P(AAm-DMC)-PAAS) are prepared. The mechanical properties of hydrogels can be effectively regulated by changing the density of chemical crosslinking and ionic crosslinking in hydrogel networks. The experimental results show that the maximum stress of the hydrogel can reach (88.4±4.7) kPa and the maximum strain is (1030.8±71.7)%. Because PAAS and DMC can ionize abundant free ions, P(AAm-DMC)-PAAS hydrogel can maintain high ionic conductivity and rapid response to stress without additional conductive filler, with conductivity up to 0.684 S/m and sensitivity factor GF about 2.409(0~70% strain range). Hydrogel can be used as a wearable strain sensor to monitor arm bending, finger bending, knee bending and other human movements through changes in relative resistance. The hydrogel can also be assembled into epidermal electrodes, which can accurately detect human physiological signals. Therefore, the P(AAm-DMC)-PAAs has the potential as a multifunctional sensor, which is expected to broaden its application in flexible electronic equipment, intelligent medical and other fields.
[Abstract](63) [FullText HTML](37) [PDF 5308KB](83)
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Polyvinylidene fluoride (PVDF) porous membrane was prepared by a two-step method of surface gel-immersion precipitation phase inversion. First, N,N-dimethyl diamide/ H2O (DMAc/H2O) mixed solutions with different volume ratios were sprayed on the PVDF solution, leading to surface gelation of the solution films. Then, the solution films with the surface gel were immersed into the deionized water of the coagulation bath to form the porous membranes by the precipitation phase inversion. The influences of spraying different DMAC volume fractions in DMAc/H2O mixed solutions（φ（DMAc））on the structures and performances of PVDF porous membranes were investigated. Results showed that as φ（DMAc） increasing, the β crystal content on the upper surface of the membranes gradually decreased, and the α crystal content gradually increased, but the overall crystallinity of the membranes gradually increased. PVDF membranes average pore size and porosity increased firstly and then reduced with φ（DMAc） increasing, and the membrane porosity greatly affect the water flux of the membrane. It was observed by scanning electron microscope (SEM) that the upper surface of the PVDF membranes sprayed with the DMAc/H2O mixed solution became a porous skin layer, and with an increment in the DMAc ratio, the spherical crystal grains on the upper surface gradually increased, and the cross sections of the membranes changed from a finger-like macroporous structure to a sponge-like pore structure. When φ（DMAc） was 0.3 , the water flux and bovine serum albumin (BSA) rejection rate of the membrane reached the maximum.
[Abstract](129) [FullText HTML](79) [PDF 6267KB](25)
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Reversible deactivation radical polymerization (RDRP) is one of the most widely used methods in the field of polymer synthesis. It can achieve precise control of molecular weight, molecular weight distribution, and polymer structure, greatly promoting the synthesis and development of functional polymer materials. Compared with traditional flask and tank reactors, the flow reactor has the advantages of large specific surface area, high mass and heat transfer efficiency, etc., which can not only effectively accelerate the reaction rate of RDRP, reduce the occurrence of side reactions, but also provides uniform and sufficient light for photo-controlled reversible deactivation radical polymerization (photo-RDRP). In addition, with the rapid development of computer science, computer-aided flow polymerization has become one of the cutting-edge technologies for polymer synthesis. This review gives an overview of the development of thermal and photo-initiated RDRP in flow chemistry at first, and then introduces the latest research progress in flow polymerization from three aspects: precise synthesis, high-throughput synthesis and self-optimized synthesis. Finally, a brief summary and prospect of the remaining problems in the flow polymerization are given.
[Abstract](117) [FullText HTML](46) [PDF 5624KB](16)
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The emergency of micro/nanoelectronic systems and miniaturized portable devices raises urgent demand on miniaturized and integrated multi-layer ceramic capacitors (MLCC). For MLCC fabrication, tape-casting technology is one of the key processes, where routinely using toluene-ethanol solution of polyvinyl butyral (PVB) as a binder Thus, the solution properties and their gelation play crucial roles in suppressing the flaws (e.g., pinhole and local heterogeneity) in the dielectric layer. However, the effects of volume ratio of toluene to ethanol have yet been investigated in details. This work decouples the effects of toluene and ethanol on the intermolecular, intramolecular and PVB-solvents interactions, and further understands the effects of solution’s compositions on gelation process. It is found that ethanol is a good solvent of PVB, through the expansion of the glassy region as structured by the packing of alkyl side chains, while toluene can effectively reduce the friction between PVB chains and solvents. Upon being exposed to atmosphere, PVB in solutions undergoes coarsening and coalescence through "nucleation-growth" mechanism. When the relative humidity is low in atmosphere, the compositional trajectory cannot cross the binodal curve and thus produce dense morphology, while high relative humidity will cause defects because the compositional trajectory crosses the binodal or spinodal curves. The defects almost do not affect the effective modulus of PVB film and thermomechanical properties. This work provides reference significance for screening PVB polymer, solvent system and film forming conditions in MLCC casting process.
[Abstract](36) [FullText HTML](19) [PDF 5334KB](3)
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The phase structures of hyperbranched epoxy resin / bisphenol A epoxy resin (EHBP-n /DGEBA) curing systems were studied by optical microscope. The relationship between the morphologies and mechanical properties of EHBP-n/DGEBA cured products was discussed. The results showed that the compatibility of the cured products was improved with the increase of EHBP-n mass fraction and the decrease of epoxy equivalent. The larger the particle size in the microstructure of the cured products was, the better the mechanical properties were. The curing process of 9%EHBP-12/DGEBA (the mass fraction of EHBP-12: 9%) was observed and the formation mechanism of homogeneous structure was proposed. The in-situ strengthening and toughening mechanism of hyperbranched polymer was confirmed. The curing kinetics of EHBP-n/DGEBA was studied by Differential Scanning Calorimetry (DSC), and the element distribution of the cured product was analyzed by Mapping. It further shows that EHBP-n has good compatibility with DGEBA, and it is a non-phase separation system after curing.
[Abstract](132) [FullText HTML](85) [PDF 5889KB](176)
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A bio-based benzoxazine (V-fa) was synthesized from furfuramine, vanillin and paraformaldehyde. Its chemical structure was characterized by Fourier-transformed Infrared (FT-IR) spectra and 1H-Nuclear Magnetic Resonance (1H-NMR) spectra. Result shows that this new benzoxazine monomer is synthesized successfully. Dicyclopentadiene-phenol epoxy resin (DCPD-ER) was selected as a research object. V-fa was added into DCPD-ER in different proportions as a latent curing agent. At the same time, a usual curing agent, diaminodiphenylmethane (DDM), was also used as a comparative study. The curing reaction of the resin system was studied by Differential scanning calorimetry (DSC) and FT-IR spectra. Results show that compared with DCPD-ER/DDM, DCPD-ER/V-fa has a higher initial curing reaction temperature and curing reaction activation energy. DCPD-ER/V-fa can cure at a high temperature, which is attributed to the reaction between phenolic hydroxyl groups produced by ring-opening reaction of the benzoxazine and epoxy groups. In addition, the thermal properties of the cured products were investigated by Dynamic Mechanical Analysis (DMA) and Thermogravimetric Analysis (TGA). Results show that the addition of V-fa can improve the heat resistance and thermal stability of the resin system. It is found that the glass transition temperature (Tg), initial decomposition temperature and char yield under nitrogen at 800 oC (Yc) of DCPD-ER/V-fa are higher than those of DCPD-ER/DDM, and the Tg and Yc can reach as high as 192 oC and 44%, respectively. Moreover, the flame retardancy of DCPD-ER/V-fa was evaluated on the basis of the results from TGA measurements. The limiting oxygen index (LOI) of DCPD-ER/V-fa can reach as high as 35.1, suggesting that the addition of V-fa improves the flame retardancy of the epoxy resin.
[Abstract](108) [FullText HTML](59) [PDF 5393KB](5)
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Nano-cobweb fibers supported by conventional electrospun fibers are 2D membranes with structure similar to spider webs, for which the average diameter is less than 50 nm and can be potentially applied in the fields of fine filter, sensor, tissue engineering, high performance protective clothing etc. Herein, polybutyrolactamide (PBL) and chitosan (CS), both derived from biomass and are biodegradable, were applied to construct the electrospun composite fiber membranes with nano-cobweb structure. The effects of blending ratio of PBL to CS and the solution concentration on solution properties as well as the fiber morphology and membrane structure were investigated. The cell compatibility of the electrospun composite fiber membranes was also discussed. It is found that the addition of polycationic CS improved the spinnability of PBL/FA solutions and the composite fibers could be continually electrospun. As the proportion of CS was increased, the conductivity and viscosity of the solutions both increased. Varying CS mass fraction in PBL/CS blend from 10% to 30% at fixed solution mass fraction of 8.0%, the solution viscosity increased even more than the conductivity did, and only fiber membranes without nano- cobweb structure were obtained. Increasing solution concentration also increased the solution conductivity and viscosity, but the increase in conductivity was more significant, which proved to be beneficial to electrospinning composite fiber membranes with nano-cobweb structure. When CS mass fraction in PBL/CS blend was 10%, increasing solution mass fraction from 8.0% to 9.0% didn’t help to get nano-cobweb structure. The nano-cobweb structure with breakages was obtained when CS mass fraction was 20% at the solution mass fraction of 10.0%. The composite fiber membranes with perfect nano-cobweb structure and 100% coverage could be electrospun by further increasing CS content and solution mass fraction to 30% and 11.0%, respectively. The results of Fourier transform infrared (FI-IR) spectroscopy and X-ray diffraction (XRD) indicated that the addition of CS inhibited the crystallization of PBL and the composite fibers of low crystallinity and even amorphous. The results of MTT assay confirmed that PBL/CS electrospun composite fiber membranes were noncytotoxic and could promote cell proliferation, especially for those with nano-cobweb structures. Such biobased and biodegradable composite fiber membranes are promising materials in the field of wound-dressing, nerve repairing and regenerative tissue engineering.
[Abstract](117) [FullText HTML](101) [PDF 5534KB](24)
Abstract:
Staphylococcus aureus (S. aureus) is one of the main pathogens causing urinary catheter-related infections, and its biofilm has strong resistance to immune clearance and antibiotics. Effective measures should be taken to solve catheter biofilm-related infections fundamentally. In this study, the host defense peptide mimicking peptide polymer was synthesized by rapid ring-opening polymerization of α-amino acid N-carboxyanhydride (NCA), which was initiated by lithium bis(trimethylsilyl)amide (LiHMDS). The resulting polymer showed a narrow molecular weight distribution. Antimicrobial experiment showed that this peptide polymer had a high bactericidal activity against the planktonic and persister cells of methicillin-resistant Staphylococcus aureus (MRSA). Bactericidal mechanism showed that this peptide polymer killed MRSA by destroying the integrity of bacterial cell membrane. Protein is one of the basic components of extracellular polymeric matrix (EPS), which plays an important role in bacterial colonization and biofilm development. The dispersing effect of protease K on EPS is beneficial to the penetration of antimicrobial agents into biofilms. 1.25 U/mL proteinase K dispersed mature MRSA biofilms in artificial urine, and the remaining cell viability was about 55% of the control group. The combination of proteinase K and polymer further eradicated mature MRSA biofilms in artificial urine, which confirmed the potential of synergism in eradicating the biofilms inside urinary catheter. The optimal combination reduced the cell viability within biofilms to about 10% of the control group.
[Abstract](150) [FullText HTML](59) [PDF 5586KB](13)
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A new type of microcapsule with self-healing and anti-corrosion function was prepared by emulsion template combined with photopolymerization and in-situ polymerization. Then the dual-functional microcapsules were dispersed in water-based epoxy resin to fabricate smart anti-corrosion coatings. In our strategy, lignosulfonate was used as an emulsifier to stabilize the oil phase composed of tung oil, glycidyl methacrylate (GMA) and 1, 6-hexanediol diacrylate (HDDA). GMA and HDDA underwent crosslinking and formed the shell of microcapsule initiated by UV light. Aniline monomer was added to the water phase subsequently and adsorbed on the outer surface of the microcapsules through the electrostatic interaction between lignosulfonate and aniline. Then the polyaniline (PANI) shell was synthesized subsequently via chemical oxidative polymerization of aniline initiated by ammonium persulfate in the water phase. The polyaniline microcapsules (Tung oil-PGMA@PANI) loaded with tung oil were prepared. The microcapsule has a composite shell structure, in which the PGMA shell layer can stabilize the emulsion droplet and improve the toughness of the microcapsule, the PANI shell layer gives the microcapsule anti-corrosion performance, and the loaded tung oil can give the microcapsule self-healing performance.The FT-IR, TGA and SEM tests proved the successful preparation of the microcapsules, and the tung oil loading in the microcapsules reached 55.1% (mass fraction). The solvent resistance result showed that the microcapsules had strong resistance to water and common non-polar solvents. The self-healing and corrosion inhibition properties of coatings were tested by microscope and salt spray test. As the mass fraction of microcapsules were 7.5%, the defects of coating could be completely repaired after 3 days, and the salt spray test results proved that the microcapsules could significantly improve the anti-corrosion performance of the smart coatings.
[Abstract](38) [FullText HTML](13) [PDF 5679KB](5)
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Graphene shows ultrafast carrier relaxation dynamics and ultra-broadband resonate nonlinear optical (NLO) response due to their extended p-conjugate system and the linear dispersion relation holding for their electronic band structure. In comparison with graphene, functionalized graphene derivatives would be expected to show more excellent NLO and optical limiting (OL) performance. By using as-synthesized graphene carbanions as initiator in the anionic polymerization, poly(N-vinylcarbazole)-covalently functionalized reduced graphene oxide (RGO) derivative (RGO-PVK) was in situ synthesized. The RGO-PVK was characterized by infrared spectroscopy, X-ray electron spectroscopy and UV-Vis absorption spectroscopy. This soluble material was embedded into an optically nonactive transparent poly(methylmeth-lacrylate) (PMMA) matrix to produce the PMMA-based RGO-PVK film for NOL and OL applications. The nonlinear optical and optical limiting properties of RGO, RGO-PVK, and annealed RGO-PVK films under 532 and 1 064 nm laser irradiation were also investigated using the open-aperture Z-scan technique.The results obtained by nonlinear fitting of the data show that in contrast to RGO, the covalent grafting of PVK chains to the RGO surface significantly improved NLO and broadband OL performance of the resultant material. Upon excitation with laser light, the achieved nonlinear coefficient (βeff) and OL threshold of the annealed RGO-PVK/PMMA film are 306.17 cm/GW and 0.37 GW/cm2 at 532 nm, and 350.32 cm/GW and 0.31 GW/cm2 at 1 064 nm. These findings would make it suitable for protecting the human eyes, optical sensors and optoelectronic devices from the laser beams in the visible and near-infrared spectral region.
[Abstract](127) [FullText HTML](51) [PDF 6629KB](28)
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Shape memory polymers (SMPs) as a kind of smart material have aroused tremendous attention including related basic frontier research and potential application duo to its advantages of light weight, larger deformed ability, as well as tunable performance. During the past years, the bulk of the research has concentrated on SMPs with relatively low to medium shape transition temperature for applications in advanced biomedical and surgical materials, smart fabrics, actuators, and so on. SMPs also have wide potential application in severe environments (high temperature, strong radiation, vacuum etc.), such as in satellites, solar arrays and antennas, shape morphing surfaces, airplane wings and aerospace self-deployable structures, where high switching temperature, extraordinary mechanical strength and excellent thermal stability are required. Recently, to meet the application needs of shape memory polymers in harsh environment, scientists have synthesized and developed a number of high performance shape memory polymers including thermoplastic and thermoset polyimide, thermoset cyanate, thermoset polyaspartimide, sulfonated poly(ether ether ketone) and so forth, these materials have high switch temperature, excellent mechanical properties and environmental tolerance. This review will introduce the latest research progress of high-temperature shape memory polymers and also its mechanism, regulation methods and typical applications will be explained and analyzed. Finally, the future development trend and challenges of high-temperature shape memory polymers are summarized and prospected.
[Abstract](64) [FullText HTML](20) [PDF 5482KB](6)
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Boron nitride nanosheets (BNNSs) is an insulating material with high breakdown strength (800 kV/mm), which is an ideal candidate for the enhancement of breakdown strength of polymer-based composites. Generally, the lateral size of BNNSs has a significant influence on thermal conductivity and mechanical properties of composites. Thus, it is worthy to further study the size effect of BNNSs on dielectric properties of composites. In this study, edge-hydroxylated BNNSs with large lateral size (l-BNNSs) and small lateral size (s-BNNSs) were respectively added into poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) to prepare BNNSs/P(VDF-HFP) composite films. The breakdown strength and dielectric constant of the composite films are tested by dielectric strength tester and broadband dielectric spectrometer to reveal the size effect of BNNSs on dielectric properties of polymer-based film capacitors. Due to the better crystal lattice of l-BNNSs and higher degree of in-plane orientation compared with s-BNNSs, the insulating network of l-BNNSs/P(VDF-HFP) composite film is more compact and perfect, which can effectively prevent the occurrence of conduction and electrical breakdown in composite films. When the mass fraction of BNNSs is 10%, P(VDF-HFP)/l-BNNSs composite films reach the highest breakdown strength (644 kV/mm). Compared with s-BNNSs/P(VDF-HFP) composite films, the breakdown strength of l-BNNSs/P(VDF-HFP) composite films has an increase of 7.65%.
[Abstract](101) [FullText HTML](38) [PDF 5640KB](93)
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Electro-driven liquid crystal elastomer (LCE) materials have broad application prospects in soft actuators, artificial muscles and micro-robots. Traditional electro-driven LCE materials are mostly prepared by doping conductive materials (carbon nanotubes, graphene, carbon black, etc.) into the polymer materials. In order to improve the conductivity, it is often necessary to increase the amount of conductive fillers, which leads to the poor mechanical properties and unsatisfactory actuation effect. To solve this problem, the liquid metal/liquid crystal elastomer (LM/LCE) composite film is prepared, then carbon black conductive filler is embedded between two LM/LCE films to obtain an electro-driven carbon black/liquid metal/liquid crystal elastomer (CB/LM/LCE) composite film with a "sandwich" structure. The composite materials are characterized and analyzed by Fourier infrared spectroscopy, differential scanning calorimetry, wide angle X-ray diffraction, scanning electron microscope, universal tensile testing instrument, etc. The results show that the LM/LCE film has excellent mechanical properties. After further embedding carbon black conductive filler between two LM/LCE films, the CB/LM/LCE composite film can perform a reversible electro-driven shrinking deformation with efficient electrothermal conversion effect. Powered by an 80 V direct current supply, the CB/LM/LCE composite film can perform a reversible shape deformation and the surface temperature increases from 30 °C to 123.8 °C in 240 s. The shrinkage rate of the CB/LM/LCE composite film reaches 18% in 130 s and the deformation shrinkage increases rapidly in the next 70 s. At 200 s, the maximum shrinkage rate can reach 45%. With a load of 50 g mass, the CB/LM/LCE composite film can still perform a remarkable reversible deformation with a maximum shrinkage rate of 42%.
[Abstract](97) [FullText HTML](48) [PDF 5474KB](85)
Abstract:
In recent years, polymer-based composites with excellent dielectric properties have recently attracted considerable interest for their potential applications in the field of microelectronics, such as electrostriction for artificial muscles, advanced dielectric capacitors and other portable flexible electronics. The combination of ceramic and conductive particles selected for the filler system has been proved to be an effective strategy to improve the dielectric properties of the polymers. The co-existence of the inorganic ceramic and conductive fillers could simultaneously contribute to the relatively higher dielectric constant and lower loss. Therefore, in this work, benefitting from the interaction between carbopol (CP) and hydroxylated barium titanate (hBT) nanoparticles, hBT surface can be coated by CP. Consequently, a core-shell structured nanoparticle was fabricated by surface modification of hBT with CP and named CP@hBT. Subsequently, the CP@hBT nanoparticle was used as the ceramic filler and the amino functionalized multiwalled nanotubes (CNT) was used as the conductive filler, polydimethylsiloxane (PDMS) as the matrix, respectively. Then CP@hBT-CNT/PDMS dielectric composites were successfully prepared by solution blending. In this work, the effect of surface modification of hBT with CP on the microstructure and the dielectric properties of CP@hBT-CNT/PDMS were systematically studied. The results indicated that the sedimentation and aggregation of CP@hBT nanoparticles can be effectively prevented after the functionalized modification of hBT by CP, thereby leading to enhanced dispersion of CP@hBT nanoparticles in PDMS matrix. As a result, with a CNT loading of 0.75% (mass fraction), the CP@hBT-CNT/PDMS composite exhibited a high dielectric constant value of 138 and low dielectric loss(<0.5) at 1 000 Hz.
[Abstract](146) [FullText HTML](82) [PDF 5562KB](92)
Abstract:
The development of high-performance memristors meets the needs of the era of big data. In particular, memristors that use organic/polymer materials with flexibly adjustable structures as the active layer are becoming increasingly popular in the field of photoelectric sensing and artificial intelligence. Inspired by mussel-inspired chemistry, a polydopamine (PDA) film was self-assembled on indium tin oxide(ITO)-coated glass substrate to form an active layer, and then grafted azobenzene (Azo) with photoisomerization properties through click chemistry to prepare the memristive device with the structure of Al/PDA-Azo/ITO, and its photoelectric performance has been studied. As a result, azo molecules are covalently grafted on the surface of polydopamine. The as-prepared device exhibits stable nonvolatile rewritable memory characteristics under applied voltage scanning. The conductivity of the device increases by 30 times after UV light irradiation, and it can be recovered after visible light irradiation, indicating that the fabricated memoristor achieves photoelectric dual response.
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2022, 35(1): 1-4.   doi: 10.14133/j.cnki.1008-9357.20211022001
[Abstract](181) [FullText HTML](76) [PDF 5023KB](55)
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Supramolecular polymers, which are chain-like aggregates of monomers connected by noncovalent interactions, possess some unique chemical and physical properties and functions. In the past thirty years, great achievements have been made in the field of supramolecular polymers. So far, there are some critical issues in this research field, including the development of the driving forces and design strategies for supramolecular polymerization, and supramolecular building blocks and functions of supramolecular polymers. Recently, for the first time, Meijer et al in Eindhoven University of Technology and Yamaguchi et al in Nagoya University incorporated the frustrated Lewis pair (FLP) into the design of supramolecular polymers. By developing FLP building blocks based on planar triarylborane and triarylamine, the supramolecular polymers were constructed based on noncovalent interactions of B−N coordination, and these polymers exhibited the unique fluorescence properties with the long lifetime and circularly polarized nature. Furthermore, Yamaguchi et al disclosed a novel supramolecular polymerization method through the design of the double-trap metastable state enabled by intramolecular hydrogen bonds and intermolecular B−N coordination, achieving dynamic and controllable supramolecular polymerization. These studies thus developed new driving forces and building blocks for supramolecular polymerization, and also provided novel design strategies for supramolecular polymerization and new functions of supramolecular polymers.
2022, 35(1): 5-18.   doi: 10.14133/j.cnki.1008-9357.20210402002
[Abstract](689) [FullText HTML](287) [PDF 16050KB](163)
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With the advent of big data and the Internet of Things (IoTs), Artificial Intelligence (AI) has received great attention from the global scientific and industrial communities. Photoelectric neuromorphic devices, which can overcome the von Neumann bottleneck issue of conventional computer systems, are developing rapidly. The optical signal, which has the advantages of low power consumption, low crosstalk, high bandwidth and low computational requirements, can be regarded as an additional terminal to enrich the regulatory freedom of synaptic plasticity. The optoelectronic performance of optoelectronic devices largely depends on the design and preparation of optoelectronic materials. With the advantages of molecular diversity, low cost, easy processing, mechanical flexibility and compatibility with flexible substrates, organic materials are important materials platform for constructing high performance optoelectronic synaptic devices. In this review, the latest development of organic materials in optoelectronic devices and visual bionics is introduced, and the current application challenges and future prospects of organic materials are discussed.
2022, 35(1): 19-35.   doi: 10.14133/j.cnki.1008-9357.20210510001
[Abstract](580) [FullText HTML](245) [PDF 6415KB](185)
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UV-curing 3D printing, one of the rapid prototyping technologies, can manufacture various complex objects by the layer-by-layer UV-curing of photosensitive resin. Comparing with other additive manufacturing technologies, it has already become one of the popular ones, due to its advantages of fast curing rate, high precision, eco-friendliness, excellent surface quality, low cost, and so on. Photosensitive resin is the preferred 3D printing main materials for high-precision products, owing to the excellent rheology properties and instant UV-curing characteristics. Generally, photosensitive resin used for 3D printing mainly consists of photosensitive prepolymers, reactive diluents, photo-initiators and a handful of additives. With the wider applications of UV-curing 3D printing, the consumption of photosensitive resin is rapidly increasing. However, there are some urgent problems to photosensitive resin, such as surface oxygen inhibition, high volume shrinkage and unsatisfactory mechanical properties. In view of the lack of systematic discussion on the latest research progress of UV-curing 3D printing and its photosensitive resin, this review focuses on the research advances and development prospect of UV-curing 3D printing and its photosensitive resin accordingly. Firstly, the printing principles and advantages and disadvantages of the universally available and newly-developed UV-curing 3D printing technologies are introduced detailly. Then, the effects of the basic compositions and molecular structures of photosensitive resins on the performances of 3D printed devices are emphatically discussed. The practical applications of UV-curing 3D printing and its photosensitive resins are also presented by living examples, including model making, industrial manufacturing and biomedical devices. Finally, the present status and future development of UV-curing 3D printing and its photosensitive resins are analyzed and prospected. This review will effectively contribute the technological progress and widen applications of UV-curing 3D printing and photosensitive resins.
2022, 35(1): 36-43.   doi: 10.14133/j.cnki.1008-9357.20210216001
[Abstract](192) [FullText HTML](86) [PDF 5574KB](53)
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The preparation of non-fluorinated proton exchange membranes (PEMs) includes post-sulfonation and direct polycondensation methods. The latter method involves the synthesis of sulfonated monomers, but the purification of sulfonated monomers is generally time-consuming. Herein, poly(arylene ether phosphine oxide)s (PAEPO) with pendant fluorenyl groups are synthesized by polycondensation of 9,9-bis(4-hydroxyphenyl) fluorene and bis(4-fluorophenyl) phenyl phosphine oxide, then the side-chain type sulfonated poly(arylene ether phosphine oxide)s (sPAEPO) are prepared by post-sulfonation as proton exchange membranes. NMR and FT-IR are used to determine the chemical structure of PAEPO and sPAEPO, and AFM is employed to characterize the microstructure of the sPAEPO PEMs. The dimensional stability and proton conductivity of the sPAEPO PEMs are also investigated. The results illustrate that the sulfonic acid groups in the side benzene rings facilitate the resultant membranes to form the microphase separation structures with well-connected hydrophilic phases, achieving high proton conductivity, low swelling, and excellent overall properties. At 80 °C, the as-made PEMs exhibit a swelling of 30%, less than that of most non-fluorinated PEMs, whereas their proton conductivity is 0.075 S/cm, close to that of Nafion 117. Besides, they also display excellent thermal stability and oxidation resistance. Therefore, the as-made PEMs show promising application prospects.
2022, 35(1): 44-53.   doi: 10.14133/j.cnki.1008-9357.20210323001
[Abstract](264) [FullText HTML](119) [PDF 5842KB](61)
Abstract:
A triblock copolymer with mussel-inspired adhesive ability, poly(acryl hydrazide)-b-poly(N-(3, 4-dihydroxyphenylethyl) acrylamide)-b-poly(monomethoxypolyethylene glycol acrylate) (PAH-b-PAD-b-PmPEGA, abbreviated as HDP), was designed and synthesized via reversible addition fragmentation chain transfer polymerization process from three monomers, including 1-tert-butcarbonyl-2-acrylhydrazide(Boc-AH), N-(3, 4-dihydroxyphenylethyl) acrylamide(DA) and poly(ethylene glycol) methyl ether methacrylate (mPEGA). The copolymer was used for decorating gold nanorod (GNR) to obtain GNR-based nanocarrier. Chemotherapeutic drug doxorubicin (DOX) was conjugated onto the nanocarrier by an acid-labile hydrazone linkage, resulting in HDP-GNR-DOX nanodrug. The physicochemical properties of the nanocarrier, such as structure, stability, photothermal performance, and pH-responsive drug release, were characterized. Moreover, the in vitro anti-tumor effect of the nanodrug towards breast cancer cells (MCF-7) was evaluated. Results showed that the DOX content of the nanodrug was as high as 8.1% and the nanodrug exhibited excellent photothermal conversion ability, favorable stability and pH-responsive drug release behavior. Importantly, the results of cellular experiments demonstrated that the nanodrug could be effectively internalized by MCF-7. In the case of near infrared irradiation, the nanodrug showed high apoptosis-inducing ability on MCF-7, achieving highly efficient photothermal-chemotherapy of breast cancer.
2022, 35(1): 54-60.   doi: 10.14133/j.cnki.1008-9357.20210330004
[Abstract](338) [FullText HTML](115) [PDF 5794KB](37)
Abstract:
In recent years, polyethylene terephthalate (PET) based Ligament Advanced Reinforcement System(LARS) artificial ligaments have become popular in anterior cruciate ligament (ACL) reconstruction. However, due to its poor biological activity and high hydrophobicity, its application is limited to clinical uses. In order to improve the biological activity of materials and enhance the tendon-bone healing effect, oxygen plasma was used to introduce hydroxyl groups on the surface of PET. It has been found that the surface physiochemical treatment and immobilization of bioactive molecules have great effects on the bioactivity improvement of the inert surfaces. Therefore, bone morphogenetic proteins (rhBMP-2) with typical indicator and fibronectin (Fn) for enhancing the binding capacity of rhBMP-2 molecules were chosen as modifying molecules. The functional molecules such as epigallocatechin-3-gallate (EGCG) were coated on the PET surface first. There are six ortho phenolic hydroxyl groups in the molecular structure of EGCG. Fn molecules were then easily immobilized on the EGCG-PET surfaces. Since each subunit of Fn had a high-affinity binding site for rhBMP-2, rhBMP-2 molecules are biological anchored on the surface through long-chained Fn, which simulates the biomimetic design in the extracellular matrix. Thus, such molecules EGCG, Fn, and rhBMP-2 are sequentially immobilized on the PET surfaces. The nanocoating of rhBMP-2/EGCG/Fn is assembled to further enhance the loading efficiency of rhBMP-2 and control the release of rhBMP-2. Therefore, the surface-modified B/E-Fn-PET exhibits excellent cell compatibility. Moreover, effective loading, activity maintaining, and controlled release of rhBMP-2 give the implant surface high osteoinduction and better osteogenesis. Predictably, the integrated influences of these factors will provide technical support for designing the insert implantable surface with high bioactivities.
2022, 35(1): 61-67.   doi: 10.14133/j.cnki.1008-9357.20210318001
[Abstract](492) [FullText HTML](242) [PDF 5547KB](49)
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Cisplatin (Cis) is one of the typical anti-tumor chemotherapeutic drugs, but its clinical application is restrained by severe toxic side effects and multidrug resistance. However, emerging nanotechnologies have great potential in overcoming the above problems. By means of the albumin templating method, an albumin/hyaluronic acid composite nanocarrier was prepared from albumin, hydrazided hyaluronic acid, and aldehyde hyaluronic acid. Cis could be loaded into the nanocarrier through Pt-hydrazide coordination chemistry. Fourier-transform infrared spectroscopy, proton nuclear magnetic resonance spectrum, transmission electron microscopy, and inductively coupled plasma mass spectrometry were employed to characterize the chemical structure of nanocarrier and the physiochemical properties of nanomedicine. The results showed that the nanomedicine exhibited a subsphaeroidal morphology with an average size of about 150 nm, and the loading content of Cis was as high as 10.8%. Moreover, the nanomedicine displayed a reduction/acid dual-responsive drug release behavior. In vitro cell experiments showed that the cytotoxicity of the nanocarrier was negligible, and the nanomedicine had good targeting ability towards hepatocellular carcinoma (HepG2) cells. Notably, the effect of nanomedicine in killing HepG2 cells was comparable to free cisplatin. Furthermore, it was found that inducing cell apoptosis was still a major mechanism of killing HepG2 cells by nanomedicine. The albumin/hyaluronic acid composite nanoparticle is a promising nanocarrier with excellent comprehensive performances for the targeting delivery of cisplatin with improved therapeutic efficacy and reduced toxic side effects in vivo .
2022, 35(1): 68-76.   doi: 10.14133/j.cnki.1008-9357.20210322001
[Abstract](353) [FullText HTML](228) [PDF 5640KB](78)
Abstract:
Quaternary ammonium salts as a kind of typical antibacterial materials, possess excellent bactericidal properties. However, most quaternary ammonium salts have the defects of low plasticity and poor film forming performance. Based on this, P(BA-co-DMAEMA) was prepared by free radical polymerization with n-butyl acrylate (BA) and 2-(diethylamino) ethyl methacrylate (DMAEMA). Then, a series of acrylic P(BA-co-DMAEMA)-R (R: bromine butane (BB), bromo hexane (HB) and bromine octane (OB) ) copolymers with different length alkanes were obtained by using BB, HB, OB as quaternization agents. Finally, P(BA-co-DMAEMA)-R films were prepared by tape casting method. The chemical structures of P(BA-co-DMAEMA) and P(BA-co-DMAEMA)-R were characterized by 1H-nuclear magnetic resonance (1H-NMR), Fourier transform infrared spectroscopy (FT-IR) and gel permeation chromatography (GPC). The mechanical properties, hydrophilicity, light transmittance of P(BA-co-DMAEMA)-R films were tested by universal mechanical testing machine, contact angle tester, UV spectrophotometer. The results show that the introduction of brominated alkanes (BB, HB, OB) could effectively improve the mechanical properties, hydrophilicity, light transmittance of the films. The elongation at break of P(BA-co-DMAEMA)-R films increases with the increase of alkane chain, the surface of the films changes from hydrophilic to hydrophobic. The transmittance of P(BA-co-DMAEMA)-R films increases with the increase of alkane chain, and the maximum transmittance is over 80%. The antibacterial properties of P(BA-co-DMAEMA)-R films are assessed by agar plate colony counting assay and zone of inhibition test. When n(BA)/n(DMAEMA) = 23/77, the quaternization degree of P(BA-co-DMAEMA)-R are 58% (BB), 45% (HB) and 39% (OB), respectively. It is observed that P(BA-co-DMAEMA)-R films exhibited outstanding broad-spectrum antimicrobial activity against S. aureus and E. coli. The antimicrobial activity is based on contact-killing of P(BA-co-DMAEMA)-R film surface, without releasing bactericidal agents, as demonstrated by the zone of inhibition test. Meanwhile, P(BA-co-DMAEMA)-R films also possess excellent antifogging performance, and its preparation process is simple and controllable, which would be used in packaging materials in the future.
2022, 35(1): 77-84.   doi: 10.14133/J.CNKI.1008-9357.20210411002
[Abstract](247) [FullText HTML](236) [PDF 5749KB](76)
Abstract:
A novel ultrasensitive impedimetric immunosensor was constructed for the detection of carcino-embryonic antigen (CEA) using conductive and adhesive bio-inspired gold/polypyrrole-polydopamine nanocomposites as an immobilization matrix. A polypyrrole-polydopamine (PPy-PDA) complex was first prepared by the polymerization of pyrrole and dopamine, which was then blended with the chloroauric acid solution (HAuCl4). The in-situ reduction of \begin{document}${\rm AuCl}_4^{\;\;-}$\end{document} to gold nanoparticles (Au NPs) by polydopamine led to the successful preparation of gold/polypyrrole-polydopamine nanocomposites (Au/PPy-PDA). Au/PPy-PDA was characterized by Fourier transmission infrared (FT-IR) spectroscopy, scanning electronic microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX) and electrical conductivity test. The dispersion test and adhesion test showed that PPy-PDA possessed good dispersibility in water and outstanding adhesion performance. The electrochemical measurement showed that Au/PPy-PDA not only provided a highly stable and biocompatible matrix for the convenient conjugation of antibody, but also accelerated the electron transfer process owing to the conductive PPy as well as encapsulated AuNPs, making it suitable to be applied as high-efficiency immunoassay platform. Under optimal conditions, a wide linear range from 10−12 ～5×10−7 g/mL and a detection limit of 0.2 pg/mL were demonstrated for the detection of CEA. Moreover, the proposed CEA immunosensor exhibited high specificity, excellent stability and reproducibility, providing an experimental evidence for early diagnosis and treatment of cancer.
2022, 35(1): 85-92.   doi: 10.14133/j.cnki.1008-9357.20210330002
[Abstract](335) [FullText HTML](222) [PDF 6058KB](67)
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Composite hydrogels PVCL with antibacterial properties were prepared by freeze-thawing method by introducing ε-polylysine(ε-PL) and citric acid (CA) into polyvinyl alcohol (PVA) aqueous solution. The structure and properties of PVCL were characterized by Fourier transform infrared spectroscopy (FT-TR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), universal tensile testing machine and swelling capacity. The biological properties of the composite hydrogels were characterized by antibacterial test, hemolysis test and cytotoxicity test. Results showed that the mechanical properties of PVA hydrogels were improved by adding CA. Compared with pure PVA hydrogel, the tensile strength of hydrogel was increased by 66.7% (from 1.8 MPa to 3.0 MPa), and the elongation at break increased by 19.8% (from 355.9% to 426.5%). However, the addition of ε-PL could reduce the mechanical properties of the hydrogels. The highest swelling rate of the composite hydrogel was 293.7%. ε-PL provided excellent antimicrobial activity for composite hydrogels. The antibacterial rate increased with the increase of ε-PL content, and the highest antibacterial rate against E.coli and S.aureus was close to 100%. In addition, PVCL had excellent hemocompatibility and cytocompatibility.
2022, 35(1): 93-100.   doi: 10.14133/j.cnki.1008-9357.20210322002
[Abstract](266) [FullText HTML](138) [PDF 5933KB](50)
Abstract:
A series of PAM-co-PDAAM-co-PNIPAM copolymers were synthesized by reversible addition fracture transfer (RAFT) polymerization from acrylamide (AM), diacetone acrylamide (DAAM) and N-isopropylacrylamide (NIPAM). Their structure and composition were characterized by Nuclear Magnetic Resonance (NMR) and Gel Permeation Chromatography (GPC). Hydrogel with pH and temperature dual-response formed by the acyl hydrazone dynamic bonds between ketocarbonyl in polymer and hydrazide in adipic dihydrazide (ADH). The dual-responsive behavior of hydrogels to temperature and pH was researched by rheological measurement, Scanning Electron Microscope (SEM) and Fourier Transform Infrared (FT-IR) spectroscopy. At the same time, the hydrogel demonstrated temperature controlled self-healing properties. Besides, the hydrogels showed pH-and temperature-responsive controlled release behaviors for doxorubicin(Dox).