College of Engineering

Little research has been conducted to determine the thermal properties and phenomena of graphane and fluorographene. A clear understanding of the thermal problems involved is needed, which may provide a basis for further research on other material properties. In the present study, molecular dynamics simulations were performed to investigate the thermal properties of graphane and fluorographene and especially the phenomena involved, including thermal fluctuations and bending rigidities. Furthermore, comparisons of thermal properties and the phenomena involved were made computationally between pristine and functionalised graphene. The thermal fluctuations and bending rigidities were determined at different temperatures. The present study aims to provide a clear understanding of the thermal problems involved in hydrogenated and fluorinated graphene. The results indicated that while thermally excited ripples spontaneously appear in graphene, fully hydrogenated or fluorinated graphene is substantially unrippled due to their very high bending rigidities. There is no significant effect of thermal rippling throughout graphane and fluorographene due to their very high bending rigidities. However, partially hydrogenated or fluorinated graphene exhibits strong thermal fluctuations. Graphene behaves differently from graphane and fluorographene with regard to the dependence of bending rigidity on temperature. Furthermore, significant out-of-plane fluctuations may occur in partially fluorinated graphene. Thermal fluctuations of graphene are more sensitive to temperature than those of graphane and fluorographene.