氧化石墨烯/聚酰亚胺相互作用及反应路径的分子动力学模拟

Molecular dynamics simulation of interaction and reaction pathways between graphene oxide and polyimide

采用分子动力学模拟的方法,建立了氧化石墨烯(GO)和聚酰亚胺(PI)的模型,探究了GO/PI复合体系中的界面相互作用,以及在2873、3073和3273 K温度下GO与PI之间的反应路径。通过分析相互作用构型演变过程、时间/相互作用能曲线和温度/相互作用能曲线,揭示了GO与PI之间存在着较强的界面相互作用,这主要源于它们都具有sp2杂化的π共轭结构。ReaxFF分子动力学模拟了GO/PI复合体系在高温下可能的反应路径,结果表明在高温下GO转变为还原GO(rGO),PI发生热解并主要引发酰胺键的断裂,形成的碳团簇碎片上的N、O活性点位与rGO发生共价键连接,并进一步促成rGO边缘新结晶碳簇的形成。温度的升高可以促进GO/PI复合体系中rGO的结晶度的增加,对rGO上的元素及碳环数量进行了分析显示rGO上新增的6元环数量由2873 K的142.1%增加到3273 K的195.3%。该研究揭示了GO/PI复合材料在高温下反应的过程,为研究高性能石墨烯膜的制备提供了重要的理论支撑。

Models of graphene oxide(GO)and polyimide(PI)were established to investigate the interface interactions in the GO/PI composite using the molecular dynamics simulation.The reaction pathways between GO and PI in the composite at different temperatures(2873,3073 and 3273 K)were also studied.A large interaction-energy between GO and PI was revealed by the evolution of the molecular configurations,time/interaction-energy curves,and temperature/interaction-energy curves due to the sp2 hybridizedπ-conjugated structures of GO and PI.ReaxFF molecular dynamics simulated potential reaction pathways at high temperatures,indicating GO transforming into reduced GO(rGO)and PI undergoing pyrolysis.The high-temperature action led to the formation of carbon clusters with N and O active sites from the pyrolytic PI covalently bonded to rGO,promoting the formation of new crystalline carbon clusters at the rGO edges.From the quantity analysis of elemental and carbon ring in the GO/PI composite,the number of newly formed hexagonal rings on rGO increased from 142.1%at 2873 K to 195.3%at 3273 K,indicating the improvement of the crystallinity of rGO by increasing action temperature.The reaction of GO/PI composite materials at high temperatures providing crucial theoretical support for the preparation of high-performance graphene membranes.