Wetting at curved substrates: Non-analytic behavior of interfacial properties

We argue that for complete wetting at a curved substrate (wall) the wall-fluid surface tension is non-analytic in R(i)(-1)i, the curvature of the wall, and that the density pro. le of the fluid near the wall acquires a contribution proportional to the gas-liquid surface tension x R-i(-1) plus higher-order contributions which are non-analytic in R-i(-1). These predictions are confirmed by results of density functional calculations for the square-well model of a liquid adsorbed on a hard sphere and on a hard cylinder where complete wetting by gas ( drying) occurs. The implications of our results for the solvation of big solvophobic particles are discussed.