Self-avoiding linear and star polymers anchored to membranes

The effect of anchored linear and star polymers in the mushroom regime on the curvature elasticity of membranes is investigated by Monte Carlo simulations and scaling arguments. We describe a simulation method to calculate the free energy of anchored polymers as a function of membrane curvature, which is accurate enough to extract reliable values for the polymer-induced spontaneous curvature Deltac(0), bending rigidity Deltakappa, and saddle-splay modulus Deltakappa;. For self-avoiding linear and star polymers, the universal amplitudes of the curvature moduli as well as the effects of finite chain lengths are determined, to our knowledge, for the first time. We find that star polymers have the unique property of strongly affecting c(0) and kappa, but leaving kappa; essentially unchanged. Furthermore, star polymers are shown to have a much stronger effect on membrane properties than an equivalent number of linear polymers.