Different Evolution Behaviors of Adhesion Force with Relative Humidity at Silica/Silica and Silica/Graphene Interfaces Studied using Atomic Force Microscopy.

The influence of relative humidity (RH) on adhesion forces demands clarification. Adhesion forces at silica/silica and silica/graphene interfaces were measured on an atomic force microscope to investigate the evolution behaviors with RH and the contact time dependence at a certain RH. For the silica/silica interface, the adhesion force at a location by decreasing RH is independent of RH, but increases as a whole with RH both at a location and in the force volume mode by increasing RH. However, for the silica/graphene interface at a location, the adhesion force remains unchanged with RH as a whole by reducing RH and tends to decrease as a whole by increasing RH. In the force volume mode, the adhesion force at the silica/graphene interface is independent of RH. For the silica/silica interface, the adhesion force increases logarithmically with dwell time at a low RH and remains unchanged at a high RH. However, for the silica/graphene interface, the force is not dependent on RH at low and high RHs. The results can serve to further understand the mechanisms and behaviors of adhesion forces and promote the anti-adhesion design for small-scale silicon-based structures.