Gas-like adhesion of two-dimensional materials onto solid surfaces

摘要

The adhesion of two-dimensional (2D) materials to other surfaces is so farbelieved to be a solid-solid mechanical contact. Here, we conduct bothatomistic simulations and theoretical modeling to show that there exists areversible conversion of energy between thermal and mechanical work in theattachment/detachment of 2D materials on/off a surface, indicating that 2Dmaterials adhesion is fundamentally like gas adsorption rather than solidadhesion. We reveal that the underlying mechanism of this intriguing gas-likeadhesion for 2D materials is the entropy difference between their freestandingand adhered states. Both the theoretical model and atomistic simulationspredict that adhesion induced entropy difference increases with increasingadhesion energy and decreasing equilibrium binding distance. The presentfindings provide a fundamental guidance toward understanding the adhesion of 2Dmaterials, which is important for designing 2D materials based devices and mayhave general implications for nanoscale efficient energy conversion.