Tippner Simon, Hernández-Castillo David, Schacher Felix H, González Leticia
Institute of Theoretical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 17, 1090 Vienna, Austria.
Doctoral School in Chemistry (DoSChem), University of Vienna, Währinger Straße 42, 1090 Vienna, Austria.
J Phys Chem B. 2025 Feb 20;129(7):2105-2114. doi: 10.1021/acs.jpcb.4c07928. Epub 2025 Feb 10.
Modeling polymer brushes is essential for understanding their complex behavior at surfaces and interfaces, enabling the design of materials with tunable properties. We present a computational protocol to model polymer brushes composed of grafted, brush-like chains of the charged polymer poly(,-dimethylaminoethyl methacrylate) (p(DMAEMA)) using an all-atom representation that captures detailed molecular interactions and structural properties. The approach is flexible and non-grid-based and allows for randomized strand configurations and the incorporation of periodic boundary conditions, enabling the construction of asymmetric polymer brush setups. An atactic p(DMAEMA) configuration is demonstrated as an example, though the protocol can be readily adapted to construct other brush-like polymer systems with varying tacticities or compositions, depending on the pH environment. Furthermore, this can be extended to stimuli-responsive materials, which generate conformation or charge upon changes in pH value or other external triggers. Molecular dynamics simulations are then employed to gain insights into the conformational behavior of the grafted p(DMAEMA) brushes and their surrounding aqueous environment, as well as their response to temperature, protonation, and variations in grafting densities, in terms of the solvent-accessible surface area, radius of gyration, and radial distribution functions. This versatile protocol provides a robust tool for simulating and analyzing the properties of diverse polyelectrolyte polymer brush systems and also as composite materials.
对聚合物刷进行建模对于理解其在表面和界面处的复杂行为至关重要，这有助于设计具有可调性质的材料。我们提出了一种计算方法，用于对由接枝的、类似刷状链的带电聚合物聚（甲基丙烯酸 - 2 - 二甲氨基乙酯）（p（DMAEMA））组成的聚合物刷进行建模，使用全原子表示法来捕捉详细的分子相互作用和结构性质。该方法灵活且基于非网格，允许随机链构型并纳入周期性边界条件，从而能够构建不对称聚合物刷结构。以无规立构的p（DMAEMA）构型为例进行了展示，不过该方法可以很容易地进行调整，以构建其他具有不同立构规整度或组成的类似刷状聚合物体系，这取决于pH环境。此外，这可以扩展到刺激响应材料，它们在pH值变化或其他外部触发因素下会产生构象或电荷变化。然后采用分子动力学模拟来深入了解接枝的p（DMAEMA）刷及其周围水环境的构象行为，以及它们对温度、质子化和接枝密度变化的响应，具体通过溶剂可及表面积、回转半径和径向分布函数来体现。这种通用方法为模拟和分析各种聚电解质聚合物刷体系以及复合材料的性质提供了一个强大的工具。
