Wang Yuling, Li Bin, Jin Haibao, Zhou Yongfeng, Lu Zhongyuan, Yan Deyue
School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China).
Chem Asian J. 2014 Aug;9(8):2281-8. doi: 10.1002/asia.201402146. Epub 2014 May 21.
Hyperbranched multiarm copolymers (HMCs) have been shown to hold great potential as precursors in self-assembly, and many impressive supramolecular structures have been prepared through the self-assembly of HMCs in solution. However, theoretical studies on the corresponding self-assembly mechanism have been greatly lagging behind. Herein, we report the self-assembly of normal or reverse vesicles from amphiphilic HMCs by dissipative particle dynamics (DPD) simulation. The simulation disclosed both the self-assembly mechanisms and dynamics of vesicles. It indicates that the self-assembly of HMCs involves several steps, from randomly distributed unimolecular micelles to small spherical micelles, to membrane-like micelles, to finally small vesicles. The membranes are formed through the direct aggregation and lateral fusion of small micelles, and the bending and closing of the membranes give rise to small vesicles. Finally, large and steady vesicles are formed through the fusion of small vesicles. In addition, the bilayer or monolayer molecular packing modes as well as the mircrophase separation behaviors of HMCs in normal or reverse vesicles have also been studied. These simulation results explore details that cannot be observed in the experiments to a certain degree, and have extended the understanding of the vesicular self-assembly process of HMCs.
超支化多臂共聚物（HMCs）已被证明作为自组装的前驱体具有巨大潜力，并且通过HMCs在溶液中的自组装已经制备出了许多令人印象深刻的超分子结构。然而，关于相应自组装机制的理论研究却大大滞后。在此，我们通过耗散粒子动力学（DPD）模拟报告了两亲性HMCs形成正常或反转囊泡的自组装过程。该模拟揭示了囊泡的自组装机制和动力学。结果表明，HMCs的自组装涉及几个步骤，从随机分布的单分子胶束到小球形胶束，再到膜状胶束，最终形成小囊泡。膜是通过小胶束的直接聚集和横向融合形成的，膜的弯曲和闭合产生小囊泡。最后，通过小囊泡的融合形成大而稳定的囊泡。此外，还研究了正常或反转囊泡中HMCs的双层或单层分子堆积模式以及微相分离行为。这些模拟结果在一定程度上探索了实验中无法观察到的细节，并扩展了对HMCs囊泡自组装过程的理解。
