Development of a radical polymerization algorithm for molecular dynamics simulations of antifreezing hydrogels with double-network structures
Development of a radical polymerization algorithm for molecular dynamics simulations of antifreezing hydrogels with double-network structures
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DOI：
10.1038/s41524-023-01161-x
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发表时间：
2023-11
影响因子：
9.7
通讯作者：
Yonglan Liu;Dong Zhang;Yijing Tang;Xiong Gong;Jie Zheng
中科院分区：
文献类型：
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作者：
Yonglan Liu;Dong Zhang;Yijing Tang;Xiong Gong;Jie Zheng
防冻水凝胶的开发和理解对于新材料的设计和交付在原理和实践上都是至关重要的。目前水凝胶中的防冻机理几乎完全来自于防冻剂的加入，而不是来自聚合物本身的固有性质。此外，开发水凝胶中独立但相互连接的双网络结构的计算模型已被证明是一项异常困难的任务。在这里，我们开发了一个多尺度模拟平台，将随机游走反应聚合(RWRP)和分子动力学(MD)模拟相结合，以模拟自由基聚合的单体，通过计算构建物理-化学连接的PVA/PHEAA DN水凝胶，并研究不同水分含量和温度下PVA/PHEAA水凝胶中的水结构、动力学和相互作用，旨在从原子水平上揭示防冻机理。集体模拟结果表明，PVA/PHEAA水凝胶的防冻性能来自于内在的强水结合网络和交联剂以及紧密交联和互穿的双网络结构的组合，这两者都增强了聚合物-水的相互作用，从而竞争性地抑制了冰核和生长。这些计算发现为水凝胶中聚合物和水分子之间的相互作用提供了原子水平的洞察，这可能决定它们的抗冻性。
The development and understanding of antifreezing hydrogels are crucial both in principle and practice for the design and delivery of new materials. The current antifreezing mechanisms in hydrogels are almost exclusively derived from their incorporation of antifreezing additives, rather than from the inherent properties of the polymers themselves. Moreover, developing a computational model for the independent yet interconnected double-network (DN) structures in hydrogels has proven to be an exceptionally difficult task. Here, we develop a multiscale simulation platform, integrating ‘random walk reactive polymerization’ (RWRP) with molecular dynamics (MD) simulations, to computationally construct a physically-chemically linked PVA/PHEAA DN hydrogels from monomers that mimic a radical polymerization and to investigate water structures, dynamics, and interactions confined in PVA/PHEAA hydrogels with various water contents and temperatures, aiming to uncover antifreezing mechanism at atomic levels. Collective simulation results indicate that the antifreezing property of PVA/PHEAA hydrogels arises from a combination of intrinsic, strong water-binding networks and crosslinkers and tightly crosslinked and interpenetrating double-network structures, both of which enhance polymer-water interactions for competitively inhibiting ice nucleation and growth. These computational findings provide atomic-level insights into the interplay between polymers and water molecules in hydrogels, which may determine their resistance to freezing.