In situ AFM investigations on degradation of self-assembled monolayers on mica: Effect of humidity

The structure and stability of self-assembled monolayers (SAMs) on substrates under certain forces are of great importance to thin films for their applications such as lubrication and adhesion in micromachines, corrosion inhibition, biological sensors, etc. In this paper, we investigate the degradation of arachidic acid (AA) monolayers on the mica surface via in situ tapping mode atomic force microscopy (TM-AFM) by continuously scanning at different humidities. Our results indicate that the degradation of AA monolayers varied along with the changing environmental humidity. The curves on the number of pinholes as a function of scan times and the dependence of the surface coverage on the scan times at varied humidity are also presented in this report. It was also found that the average apparent height of AA monolayers decreased with the increasing relative humidity.