ABSTRACT
Theory, numerical simulations, and experiments on the stability, dynamics, morphology and dewetting of thin (<100 nm) films on variously modified solid surfaces are presented. Results for two distinct types of thin films are presented in greater details: (1) films subjected to the long range van der Waals attraction and extremely short range Born repulsion, and (2) films subjected to the long range attraction combined with shorter range repulsion. In the first case, true dewetting (adhesion failure) occurs in the form of growing holes which eventually coalesce to form a giant polygonal structure. The number density, growth rates and the morphology of rims are characterized for growing holes. In the second case, saturation of the initial instability leads to a quasi-stable interconnected microstructure consisting of an array of small droplets in equilibrium with largely flat thin regions. This ‘morphologically phase separated’ (MPS) structure slowly coarsens by ripening (merger) of drops due to spatial gradients of curvature and disjoining pressure. Nonadsorbing polystyrene (PS) films on variously modified nonwettable silicon wafers, and on densely grafted PS ‘brushes’, show true dewetting. In contrast, PS and PS–PEO (a block copolymer) films adsorbed on UV-ozone treated wafers show the MPS and ripening.
