▎ 摘　　要

The evaporation processes of water from the edge region of graphene sheets was investigated by means of the direct molecular orbital-molecular dynamics (MO-MD) method at the AM1 level. Five graphenes with n = 1, 7, 19, 37, and 61 (where n is the number of benzene rings in the graphene) were examined as models of graphene sheets. The edge carbons of each graphene were terminated by hydrogen atoms. In the H2O-graphene interaction system, the oxygen atom of the water molecule binds to one or two C-H hydrogen atoms of the edge carbons. The binding energy of H2O increased gradually as a function of n and was saturated around n = 61. At low temperature (10-100 K), the water molecule was still connected to the graphene sheet, whereas the evaporation of H2O was found above 300 K. The mechanism of water evaporation is discussed on the basis of theoretical results. (C) 2010 The Japan Society of Applied Physics