水环境下氧化石墨烯/水化硅酸钙脱粘动力学特性研究

Study on the kinetic properties of graphene oxide/calcium silicate hydrate in water environment

摘要:

本研究采用分子动力学揭示了GO/C-S-H界面作用机制。发现GO表面羧基通过O=COOH-Hw强氢键与Ca-O离子键网络协同作用,界面结合能较环氧基/羟基体系提升61.1%-65.2%。温度-湿度耦合呈现阈值效应：275-325 K时每升温10 K结合能下降9.8%,吸附水>2层后界面性能指数衰减。3层GO通过层间应力传递与水结构重构协同增效,脱粘功提升136%,但需优化堆叠层数防止缺陷。基于模拟结果,构建了 官能团修饰-水含量调控-层结构优化 协同策略,揭示GO官能团通过调控界面水结构主导结合性能的规律。研究阐明温度/湿度/层数多因素耦合作用机制,为设计高耐久纳米混凝土提供了界面水结构调控的量化设计框架。

Abstract:

In this study, molecular dynamics was used to reveal the mechanism of the GO/C-S-H interface. It was found that the carboxyl group on GO surface synergistically acted with the Ca-O ionic bond network through O=COOH-Hw strong hydrogen bond, and the interface binding energy was increased by 61.1%-65.2% compared with the epoxy group/hydroxyl group system. The temperature-humidity coupling showed a threshold effect: the binding energy decreased by 9.8% at 275-325 K for every 10 K of temperature increase, and the interface properties decreased exponentially after adsorbing water >two layers. Through the synergistic effect of interlayer stress transfer and water structure reconstruction, the three-layer GO can improve the debonding work by 136%, but the number of stacked layers needs to be optimized to prevent defects. Based on the simulation results, a collaborative strategy of "functional group modification-water content regulation-layer structure optimization" was constructed to reveal the law of GO functional group leading binding performance by regulating the interfacial water structure. This study elucidates the multi-factor coupling mechanism of temperature/humidity/layer number, which provides a quantitative design framework for the control of interfacial water structure in the design of nano-concrete with high durability.