水溶液中石墨烯剥离的分子动力学模拟

摘要

The thermodynamics mechanism for exfoliating a flexible graphene layer in water media was investigated using molecular dynamics simulation.To characterize the interactions between water solvent molecules and graphene,the structure properties of the water around graphene were discussed,the change of the free energy of the system was calculated,the microstructure change in the process of stripping and the structure properties of water solvent around grephene were analyzed.The results showed that the interaction between graphene and the water was very small.There existed a significant free energy barrier hindering exfoliation.The decomposition of the free energy showed that the interaction between graphene sheets mainly determined the free energy barrier.The solvent provided a favorable contribution to exfoliation,and the confined solvent played an important role in graphene exfoliation.%通过分子动力学模拟方法研究柔性石墨烯在水溶液中剥离的热力学机制.为了表征石墨烯与水溶剂之间的相互作用,研究了石墨烯周围水溶剂的结构性质；通过施加外力的方法剥离石墨模型中最外层的石墨烯,计算剥离过程中体系自由能的变化,并对剥离过程中微观结构变化以及石墨烯周围水溶剂结构性质进行分析.结果表明:石墨烯与水之间的相互作用较小；剥离石墨烯需要克服一定的能垒；石墨烯之间的相互作用决定了自由能能垒的大小,溶剂诱导的贡献对剥离起到促进作用；受限区域内的水溶剂分子对剥离起到重要的作用.