Metal – polymer interactions are widely exploited for the formation of composite polymer materials, such as hydrogels. Despite the interest towards these systems, still few information is available about the atomistic structure of contacts formed at the interface between the polymer chains, as well as interactions responsible for their formation. In this work the interface formed through the interaction between a widely used polymer system – polymethacrylic acid (PMAA) and Ca²⁺ cation, as a frequently applied metal cross-linker, is investigated by an ab initio modeling. The local environment of Ca binding sites, including coordination patterns of carboxylic groups, the maximum number of chains cross-linked by one Ca cation, as well as the impact of the PMAA protonation state on the polymer cross-linking are studied. The dynamics of Ca cross-linking process in polymer-rich environment is analyzed. These findings shed the light on the mechanism of Ca – PMAA hydrogel formation and provide the atomistic scale insights on the structure of metal cross-links in the polymer environment, necessary for the optimization of experimental conditions required to obtain polymer composites with enhanced stability and targeted functional characteristics.

金属与聚合物之间的相互作用被广泛用于形成复合聚合物材料，例如水凝胶。尽管对这些系统感兴趣，但是关于在聚合物链之间的界面处形成的接触的原子结构以及导致它们形成的相互作用的信息仍然很少。在这项工作中，从头开始研究了通过广泛使用的聚合物体系-聚甲基丙烯酸（PMAA）和Ca ²⁺阳离子（作为一种常用的金属交联剂）之间的相互作用而形成的界面。造型。研究了Ca结合位点的局部环境，包括羧基的配位方式，被一个Ca阳离子交联的最大链数以及PMAA质子化态对聚合物交联的影响。分析了富含聚合物的环境中Ca交联过程的动力学。这些发现揭示了Ca-PMAA水凝胶形成的机理，并提供了在原子级规模上洞悉聚合物环境中金属交联结构的知识，这对于优化获得增强了稳定性和针对性的聚合物复合材料所需的实验条件是必要的功能特点。