Novel Diffusion Mechanism of Polymers Pinned to an Attractive Impurity.

Actual substrates unavoidably possess, to some extent, defects and dirt, which motivate understanding the impact due to their presence. The presence of a substrate naturally breaks symmetries. Additionally, it effectively reduces spatial dimensionality, which favors fluctuation-dominated behavior, but it also provides a multitude of possible interactions. We show evidence of novel behavior in the case of polymer mass transport at a crystalline substrate when a single attractive impurity is present. Specifically, we introduce a model system describing how an attractive impurity pins adsorbed polymers on a substrate. We propose a novel mechanism to explain the size scaling dependence of the diffusion coefficient as D∼N-3/2 for polymers with N monomers. Additionally, the size dependence of the diffusion coefficient scales can be described as D∼N-δ, with δ=1.51 as determined from extensive simulations.