NONMONOTONIC EXTENSION OF POLYMERS IN APERIODIC POTENTIALS

We study polymer chains embedded in regular lamellar matrices (i.e., m icrophase separated block copolymer melts). In such quasi-1D systems t he host acts as a nearly periodic external potential. A probe chain ge ts trapped with localization length L at isolated defects, when its de gree of polymerization N exceeds a (system-dependent) crossover value N-L. Increasing the defect density rho from low values, the chains get gradually localized until saturation is reached. At higher rho, bridg ing occurs and the chains spread over several defects. As a result the chain's radius of gyration shows a minimum.