Localization Transition of Random Chains at Interfaces.

We consider a simple model of a random chain at an interface between two fluids, and suppose that its monomers have random affinities with both fluids (e.g. a Gaussian distribution with mean value xi sub o). Simple statistical arguments and replica theory lead to the prediction of a localization transition of the chain (for the generic case of non-zero xi sub o). This transition separates a low temperature phase, in which the random chain is localized at the interface, from a high temperature phase in which it is delocalized in one solvent. This physical picture is qualitatively confirmed by numerical studies.