STATIC AND DYNAMICAL STRUCTURE OF CONFINED POLYMER-FILMS

The static and dynamical structure of confined polymer films are discussed by considering recent measurements of (i) the static forces required to compress polymer films to nanometer-level thickness and (ii) the associated dynamic oscillatory shear response. The static force-distance profiles, unlike those typical of small molecules, are monotonically repulsive. In addition, the storage and loss shear moduli follow patterns that are qualitatively similar to entanglement effects in bulk isotropic polymer melts, with the exception that entanglements appear to be enhanced in the confined films. Speculative interpretations are advanced.