Structures of Hierarchical Nanowires Analyzed by Static Light Scattering Characterization and Dissipative Particle Dynamics Simulation

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.