6533b827fe1ef96bd12871ed

RESEARCH PRODUCT

Surface-directed phase separation with off-critical composition: Analytical and numerical results

subject

description

We study the interplay of wetting and phase separation in an unstable binary mixture $(\mathrm{AB})$ with off-critical composition, placed in contact with a surface which prefers the component $A.$ We consider surface potentials $V(z)\ensuremath{\sim}{z}^{\ensuremath{-}n},$ where z is the distance from the surface, and present analytical arguments and detailed numerical results to elucidate wetting-layer kinetics for arbitrary mixture compositions. If the preferred component is the minority phase, the wetting-layer thickness exhibits a potential-specific behavior at early times $\ensuremath{\tau},$ ${R}_{1}\ensuremath{\sim}{\ensuremath{\tau}}^{1/(n+2)},$ before crossing over to the universal growth law, ${R}_{1}\ensuremath{\sim}{\ensuremath{\tau}}^{1/3}.$ On the other hand, if the preferred component is the majority phase, there is a crossover from potential-specific growth (as before) to a slower growth regime.