A New Approach to Examine Interfacial Interaction Potential between a Thin Solid Film or a Droplet and a Smooth Substrate

Abstract

Atomic force microscopy (AFM) technique has been successfully used to study the sublimation rate of explosive solid film on a smooth surface. Based on the experimental results, a dipole-induced dipole propagation potential is employed to explain a nonlinear sublimation rate of solid TNT thin film very close to the interface. In this model, three important physical parameters, bulk TNT sublimation rate δ0, surface interaction potential U o and the effective range of the surface potential h o , are introduced with no arbitrary constants. It is argued that this type of model reflects a general phenomena rather than a special case. This model has been further extended to describe the evaporation rate of liquid droplets resting on a smooth surface. It is also demonstrated that tapping mode AFM is capable of imaging highly viscous explosive droplets under ambient conditions.