Departamento de Química Fundamental , Universidade Federal de Pernambuco , Cidade Universitária, 50670-901 Recife , Brazil.
Department of Chemistry , Umeå University , 90187 Umeå , Sweden.
Langmuir. 2019 Apr 9;35(14):5037-5049. doi: 10.1021/acs.langmuir.8b04268. Epub 2019 Mar 26.
The complex solution behavior of polymer brushes is key to control their properties, including for biomedical applications and catalysis. The swelling behavior of poly(dimethyl aminoethyl methacrylate) (PDMAEMA) and poly(2-(methacryloyloxy)ethyl trimethylammonium chloride) (PMETAC) in response to changes in pH, solvent, and salt types has been investigated using atomistic molecular dynamics simulations. PDMAEMA and PMETAC have been selected as canonical models for weak and strong polyelectrolytes whose complex conformational behavior is particularly challenging for the development and validation of atomistic models. The GROMOS-derived atomic parameters reproduce the experimental swelling coefficients obtained from ellipsometry measurements for brushes of 5-15 nm thickness. The present atomistic models capture the protonated morphology of PDMAEMA, the swollen and collapsed conformations of PDMAEMA and PMETAC in good and bad solvents, and the salt-selective response of PMETAC. The modular nature of the molecular models allows for the simple extension of atomic parameters to a variety of polymers or copolymers.
聚合物刷的复杂溶液行为是控制其性能的关键，包括在生物医学应用和催化方面。使用原子分子动力学模拟研究了聚（二甲基氨基乙基甲基丙烯酸酯）（PDMAEMA）和聚（2-（甲基丙烯酰氧基）乙基三甲基氯化铵）（PMETAC）对 pH 值、溶剂和盐类型变化的溶胀行为。PDMAEMA 和 PMETAC 被选为弱和强聚电解质的典型模型，其复杂的构象行为对原子模型的开发和验证特别具有挑战性。基于 GROMOS 的原子参数再现了从椭圆光度法测量获得的 5-15nm 厚度刷的实验溶胀系数。本原子模型捕获了 PDMAEMA 的质子化形态、良好和不良溶剂中 PDMAEMA 和 PMETAC 的溶胀和塌陷构象，以及 PMETAC 的盐选择性响应。分子模型的模块化性质允许简单地将原子参数扩展到各种聚合物或共聚物。
