Multiscale Simulation of the Mushroom-Shaped Nanoscale Supramolecular System: From Self-assembly Process to Functional Properties

摘要

The miniaturized rod-coil triblock copolymers BPEIS ((biphenyl ester)~3-(isoprene)~9-(styrene)~9) had been found to self-assemble into well-ordered nanostructures and unusual head to tail multilayer structure. The purpose of our study is to obtain fundamental understanding the connection of the inherent morphological characterization of single molecule and the mechanism of phase behavior of this polar self-assembly system, which result in significant optical properties. Dissipative particle dynamics simulation was carried out to study the mechanism of phase behavior of the solvent-copolymers system. We found that the solvent-induced polar effect under different temperature is important in the process of self-assembly of block copolymers. In different temperature the solvent induces hybrid structure aggregation. Our results are consistent with experimental observations and give more understanding of the mechanism governing the self-assembly process and phase behavior. Furthermore, the sizes and stabilization energies of mushroom-shaped supramolecular clusters were predicted by molecular modeling method. Clusters of sizes from 16 to 90 molecules were found to be stable. In combination of classical and simple quantum mechanical calculations, the band gaps of BPEIS clusters with various sizes were estimated. The band gap was converged at 2.45 eV for cluster contains 90 molecules. Nonlinear optical properties of the material were investigated by the semi-empirical quantum mechanical calculations of molecular dipole moment and hyperpolarizabilities. Significant second-order nonlinear optical properties were shown from these calculated properties.