Surface polymer network model and effective membrane curvature elasticity.

A microscopic model of a surface polymer network membrane system is introduced, with contact polymer surface interactions that can be either repulsive or attractive and sliplinks of functionality four randomly distributed over the supporting membrane surface anchoring the polymers to it. For the supporting surface perturbed from a planar configuration and a small relative number of surface sliplinks, we investigate an expansion of the free energy in terms of the local curvatures of the surface and the surface density of sliplinks, obtained through the application of the Balian Bloch Duplantier multiple surface scattering method. As a result, the dependence of the curvature elastic modulus, the Gaussian modulus as well as of the spontaneous curvature of the ”dressed” membrane, i.e. polymer network plus membrane matrix, is obtained on the mean polymer bulk end to end separation and the surface density of sliplinks. PACS. 82.70 Disperse systems. PACS. 05.20 Statistical Mechanics. PACS. 61.25H Macromolecular and polymer solutions. February 1, 2008 ∗On leave from J.Stefan Institute, P.O.B. 100, 61000 Ljubljana, SLOVENIA.