Structural and thermodynamic properties of end-grafted polymers on curved surfaces

Abstract

Conformational and thermodynamic properties of polymer chains end-grafted to cylindrical and spherical surfaces under good solvent conditions have been studied using the single-chain mean-field theory. We have considered chains of 50, 100, and 150 segments, and five different radii from R=2 up to R=100. We have found excellent quantitative agreement with all the available molecular dynamics and Monte Carlo simulations for the conformational properties at all curvatures. Further, the chemical potential of the chains for planar geometries is found to be in excellent agreement with recent Monte Carlo simulations. In the limit of strong curvature for the cylindrical geometry our findings qualitatively agree with the analytical prediction of Li and Witten for the structure but not for the polymer free energy. The chemical potential of the grafted chains was calculated as a function of the surface coverage and the radius of curvature of the surface. Our findings suggest that for all curvatures and surface coverage the chemical potential has to be properly calculated to obtain realistic adsorption isotherms.