EFFECT OF SURFACE-ROUGHNESS ON BULK-DISORDER-INDUCED WETTING

Transfer-matrix results in 2D show that wetting of a rough, self-affin e wall induced by bulk bond disorder turns discontinuous as soon as th e wall roughness exponent zeta w exceeds zeta(0) = 2/3, the spatial an isotropy index of interface fluctuations in the bulk. For zeta(W) < 2/ 3 critical wetting is recovered, in the same universality class as for the flat-wall case. These and related findings suggest a free-energy structure such to imply first-order wetting also without disorder, or in 3D, whenever zeta(W) exceeds the appropriate zeta(0). The same thre sholds should apply also with van der Waals forces, in cases when Co i mplies a strong-fluctuation regime.