End-capped associative polymer chains between nanospheres: Attractions in ideal solutions

We calculate equilibrium configurations of telechelic associative polymer chains without excluded volume interactions between flat plates and curved surfaces, obtaining analytical expressions for flat; plates and numerical results for chains between two spheres. Ideal chains with strongly but reversibly adsorbed terminal groups produce an attraction of O(kT) per chain for planar surfaces as opposed to much less than kT per chain in marginal and good solvents at high densities. Our numerical results for two spheres yield a weaker repulsion and an attraction of shorter range than predicted by the Derjagain approximation based on the nat plate solution. These effects are due to deflection of chains out of the gap at close separations.