Yang Xiao, Qi Hang-Kai, Yang Qing-Hui, Wang Chao, Luo Meng-Bo
Department of Physics, Taizhou University, Taizhou, Zhejiang 318000, China.
Department of Physics, Zhejiang University, Hangzhou, Zhejiang 310027, China.
Langmuir. 2023 Apr 4;39(13):4847-4854. doi: 10.1021/acs.langmuir.3c00411. Epub 2023 Mar 21.
Mixed brushes consisting of flexible and semiflexible polymers of the same chain length exhibit a height-switching phenomenon because of rigidity-dependent critical adsorption [Yang et al. 2020, 53, 7369]. Semiflexible polymers stand higher at weak surface attraction (high temperature), but they close to the attractive surface at strong attraction (low temperature). In this work, the height-switching dynamics of the mixed polymer brushes is studied by Metropolis Monte Carlo simulation. The height-switching time is calculated by a sudden change in the surface attraction. Two surface attraction change modes, i.e., the weak-to-strong mode where the attraction is changed from weak to strong and the strong-to-weak mode where it is changed from strong to weak, are investigated. Simulation results show that the height-switching time is related to the grafting density, the polymer stiffness, and surface attraction change mode. We find that the height-switching time is significantly decreased for the strong-to-weak mode. And our results also show that the height switching in the mixed polymer brushes is reversible.
由相同链长的柔性和半柔性聚合物组成的混合刷由于刚性依赖的临界吸附而表现出高度切换现象[Yang等人，2020，53，7369]。半柔性聚合物在弱表面吸引力（高温）下站立得更高，但在强吸引力（低温）下它们靠近吸引表面。在这项工作中，通过 metropolis 蒙特卡罗模拟研究了混合聚合物刷的高度切换动力学。高度切换时间通过表面吸引力的突然变化来计算。研究了两种表面吸引力变化模式，即从弱到强的弱到强模式和从强到弱的强到弱模式。模拟结果表明，高度切换时间与接枝密度、聚合物刚度和表面吸引力变化模式有关。我们发现，强到弱模式下的高度切换时间显著缩短。并且我们的结果还表明，混合聚合物刷中的高度切换是可逆的。
