Effect of Chain Stiffness on the Adsorption Transition of Polymers

Polymers grafted with one chain end to an impenetrable flat hard wall which attracts the monomers with a short-range adsorption potential (of strength ε) are studied by large scale Monte Carlo simulations, using the pruned–enriched Rosenbluth method (PERM). Chain lengths up to N = 25600 steps are considered, and the intrinsic flexibility of the chain is varied via an energy penalty for nonzero bond angles, ε b . Choosing q b = exp(−ε b / k B T ) in the range from q b = 1 (fully flexible chains) to q b = 0.005 (rather stiff chains with a persistence length of about lattice spacings), the adsorption transition is found to vary from about ε/ k B T c ≈ 0.286 to ε/ k B T c ≈ 0.011, confirming the theoretical expectation that for large . The simulation data are compatible with a continuous adsorption transition for all finite values of, while in the rigid rod limit ( ) a first order transition seems to emerge. Scaling predictions and blob concepts on the structure of weakly adsorbed semiflexible polymers absorbed at interfaces are briefly discussed.