Spinodal dewetting of liquid-liquid thin-films

The spinodal dewetting of a thin liquid polystyrene (PS) film from a liquid polymethylmethacrylate (PMMA) substrate is investigated experimentally and theoretically. Comparing experimental results of the evolving PS-air and PS-PMMA interfaces with the predictions from linear stability analysis shows that both spinodal wavelength and rupture times deviate unexpectedly. The key factor for this discrepancy is the altered mode selection process due to the initial surface roughness of the liquid-air and liquid-liquid interfaces perturbed by partially correlated colored noise in the linearly unstable region. The strong impact of noise on the mode selection and on the rupture time is clearly demonstrated through long-time numerical solutions of the full nonlinear model when compared to experimental results. This strong impact of noise is relevant only for liquid bilayers, and not for spinodal dewetting on solids, due to the presence of two moving interfaces and calls for new strategies to incorporate also thermal fluctuations into the modelling of those systems.