机械剥离过程中石墨晶体结构内能量相互作用的机理分析（英文）  

Analysis of the interaction energies between and within graphite particles during mechanical exfoliation

作　　者：尹力 邓钏 邓斐 葛晓陵[1] YIN Li;DENG Chuan;DENG Fei;GE Xiao-ling(School of Mechanical and Power Engineering,East China University of Science and Technology,Shanghai 200237,China;Department of Material Science and Engineering,Chongqing Jiaotong University,Chongqing 400047,China)

机构地区：[1]华东理工大学机械与动力工工程学院,上海200237 [2]重庆交通大学材料科学与工程学院,重庆400047

出　　处：《新型炭材料》2018年第5期449-459,共11页New Carbon Materials

基　　金：上海市科委纳米专项基金(0652nm001)~~

摘　　要：通过分析机械剥离过程中石墨颗粒的厚度方向和横向尺寸分布变化,建立了计算石墨片体与石墨片单层之间能量相互作用的机械模型。表征分析了剥离过程中石墨晶体结构的变化趋势。分别分析计算了石墨片剥落过程中的范德华能、石墨片单层断裂过程中的共价键能、片体以及片单层各自团聚过程中的势能。结果表明,两个石墨片单层之间的范德华力作用是导致片单层团聚的关键因素;随着剥离过程的进行,团聚现象逐渐超过剥离现象。石墨片单层剥离过程中的范德华能是片单层团聚过程中的势能的1/4,并且比石墨块体断裂过程中的共价键能小2个数量级。随着剥离出的石墨片体和片单层数量的增加,由于晶体结构间范德华能的释放而导致团聚现象急剧增加;剥离过程中的库伦能比较微小可以忽略不计。该机械模型对于制备高纵横比和无团聚的石墨片层材料具有重要意义。A method for calculating the interaction energies between and within graphite particles is established by analyzing their thickness and lateral size distribution from AFM and SEM images of 300 particles during mechanical exfoliation at different times.The energy for exfoliating graphite sheets by breaking van der Waals(vdW)bonds,the energy for fracturing graphite sheets by breaking covalent bonds,the potential energies for restacking graphite sheets and the lateral aggregation of graphite particles are analyzed.Results show that the vdW interaction between graphite sheets is the key factor that leads to their restacking.Restacking and lateral aggregation become more active than exfoliation as exfoliation progresses.The energy for exfoliating graphite sheets by breaking vdW bonds is 4 times less than that the potential energy for restacking graphite sheets,and 2 orders of magnitude less than that the energy for fracturing graphite sheets by breaking covalent bonds.The increased number of exfoliated and fractured graphite sheets leads to a considerable increase in the restacking and lateral aggregation by vdW interaction.The coulombic energy is weak and can be ignored.The model has implications for the fabrication of aggregation-free graphite sheets with high aspect ratios.

关 键 词：机械剥离 能量相互作用 范德华能 团聚势能 

分 类 号：TQ165[化学工程—高温制品工业]