Mechanical buckling induced periodic kinking/stripe microstructures in mechanically peeled graphite fla es from HOPG  

作　　者：Manrui Ren Ze Liu Quan-shui Zheng Jefferson Zhe Liu 

机构地区：[1]Department of Engineering Mechanics and Center for Nano and Micro Mechanics, Tsinghua University [2]Department of Mechanical and Aerospace Engineering,Monash University

出　　处：《Acta Mechanica Sinica》2015年第4期494-499,共6页力学学报（英文版）

基　　金：financia support from NSFC(Grant 10832005);the National Basic Research Program of China(Grant 2007CB936803);the National 863 Project(Grant2008AA03Z302);the support from the engineering faculty of Monash University through seed grant 2014

摘　　要：Mechanical exfoliation is a widely used method to isolate high quality graphene layers from bulk graphite. In our recent experiments, some ordered microstructures, consisting of a periodic alternation of kinks and stripes, were observed in thin graphite flakes that were mechanically peeled from highly oriented pyrolytic graphite. In this paper, a theoretical model is presented to attribute the formation of such ordered structures to the alternation of two mechanical processes during the exfoliation： （1） peeling of a graphite flake and （2） mechanical buckling of the flake being sub- jected to bending. In this model, the width of the stripes L is determined by thickness h of the flakes, surface energy Y, and critical buckling strain ecr. Using some appropriate values of y and ecr that are within the ranges determined by other inde- pendent experiments and simulations, the predicted relations between the stripe width and the flake thickness agree reason- ably well with our experimental measurements. Conversely, measuring the L-h relations of the periodic microstructures in thin graphite flakes could help determine the critical mechan- ical buckling strain εcr and the interface energy γ.Mechanical exfoliation is a widely used method to isolate high quality graphene layers from bulk graphite. In our recent experiments, some ordered microstructures, consisting of a periodic alternation of kinks and stripes, were observed in thin graphite flakes that were mechanically peeled from highly oriented pyrolytic graphite. In this paper, a theoretical model is presented to attribute the formation of such ordered structures to the alternation of two mechanical processes during the exfoliation： （1） peeling of a graphite flake and （2） mechanical buckling of the flake being sub- jected to bending. In this model, the width of the stripes L is determined by thickness h of the flakes, surface energy Y, and critical buckling strain ecr. Using some appropriate values of y and ecr that are within the ranges determined by other inde- pendent experiments and simulations, the predicted relations between the stripe width and the flake thickness agree reason- ably well with our experimental measurements. Conversely, measuring the L-h relations of the periodic microstructures in thin graphite flakes could help determine the critical mechan- ical buckling strain εcr and the interface energy γ.

关 键 词：HOPG Mechanical exfoliation Periodic microstructures KINKING Mechanical buckling 

分 类 号：O344.1[理学—固体力学]