We study the macroscopic behavior of homopolymers and block copolymers at the interface of two different phases focusing on the random walk nature of the polymer chains. The macromolecules or parts of them can belong to either one of the phases and are described by a simple model of random walks according to which the chain parts can have different average sizes depending on the phase they belong. Though the exact description of polymer chains under additional potentials need non-ideal walks, the present effort can be considered as an initial study seeking the effects of the differentiation of the size of the chains in the two phases because of the different interactions. The way of settling of chains in the two phase system is determined by means of the connection of the weights of the macrostates of localized chains with the probability distributions of the positions of the chain units. Density profiles of both homopolymers and diblock copolymers along the direction perpendicular to the interface are well described and the study is extended to miktoarm star macromolecules made from different homopolymeric arms.