Ma Zengwei, Liu Gaiqin, Hu Nan, Chen Lin, Wei Jianwei
College of Science, Chongqing University of Technology Chongqing 400054 China
RSC Adv. 2024 Aug 2;14(33):24240-24249. doi: 10.1039/d4ra04511d. eCollection 2024 Jul 26.
The self-assembly of miktoarm star polymers μ-A (B(D)) C in a neutral solution and the pH-responsive behaviors of vesicles and spherical micelles in an acidic solution have been investigated by DPD simulation. The results show that the self-assembled morphologies can be regulated by the lengths of pH-responsive arm B and hydrophilic arm C, leading to the formation of vesicles, discoidal micelles, and spherical micelles in a neutral solution. The dynamic evolution pathways of vesicles and spherical micelles are categorized into three stages: nucleation, coalescence, and growth. Subsequently, the pH-responsive behaviors of vesicles and spherical micelles have been explored by tuning the protonation degree of pH-responsive arm B. The vesicles evolves from nanodisks to nanosheets, then to nanoribbons, as the protonation degree increases, corresponding to a decrease in pH value, while the spherical micelles undergoes a transition into worm-like micelles, nanosheets, and nanoribbons. Notably, the electrostatic interaction leads the counterions to form a regular hexagonal pattern in nanosheets, while an alternative distribution of charged beads has been observed in nanoribbons. Furthermore, the role of the electrostatic interaction in the morphological transition has been elucidated through the analysis of the distribution of positive and negative charges, as well as the electrostatic potential for associates.
通过耗散粒子动力学（DPD）模拟研究了米克托臂星形聚合物μ-A （B（D）） C在中性溶液中的自组装以及囊泡和球形胶束在酸性溶液中的pH响应行为。结果表明，自组装形态可通过pH响应臂B和亲水臂C的长度进行调节，从而在中性溶液中形成囊泡、盘状胶束和球形胶束。囊泡和球形胶束的动态演化途径分为三个阶段：成核、聚结和生长。随后，通过调节pH响应臂B的质子化程度，探索了囊泡和球形胶束的pH响应行为。随着质子化程度增加，对应于pH值降低，囊泡从纳米盘演变为纳米片，然后变为纳米带，而球形胶束则转变为蠕虫状胶束、纳米片和纳米带。值得注意的是，静电相互作用导致抗衡离子在纳米片中形成规则的六边形图案，而在纳米带中观察到带电珠子的交替分布。此外，通过分析正负电荷分布以及缔合体的静电势，阐明了静电相互作用在形态转变中的作用。
