Analysis of liquid mediated contact of glass colloidal particle with polystyrene coated surface

Spin coating has been widely used for obtaining uniform thin polymeric coating over glass surfaces. Previous studies have shown that the thin-coated film can deform and bulge out upon immersion in liquid. Such deformations can affect various properties of the films. In this study, we have analyzed the interaction of glass colloidal particle and the polystyrene (PS) spin-coated surface immersed in deionized (DI) water. It was found that the glass colloidal particle interacts with the surface in dissimilar way at various locations on the surface. A sudden reduction in the forces was also observed at different locations on the same surface. The separation distances at which the sudden change in the force occurred was closer to the height of the spherical domains. Therefore, the change could be attributed to the presence of blisters on the surface formed due to permeation of water into the thin film-substrate interface.