We are attempting to design polymer-polymer interfaces by specific acid-base interaction of functional groups on a polymer surface with functional groups on the free polymer in solution. Poly(vinylidene fluoride) (PVF2) was chosen as a substrate. We found that PS-COOH adsorbs to PVF2-NH2 from CH at 36°C. The rate of adsorption depends on two processes, each with its own: the initial attachment of at least one segment to the surface (depends on diffusion and hence molecular weight and concentration gradient) and the subsequent attachment of additional segments.