Breakdown of the Kratky-Porod wormlike chain model for semiflexible polymers in two dimensions

¹ Institut für Physik, Johannes Gutenberg Universität Mainz - Staudinger Weg 7, 55099 Mainz, Germany
² Theoretische Physik, Martin-Luther-Universität Halle Wittenberg - von Senckendorffplatz 1, 06120 Halle, Germany

^a hsu@uni-mainz.de

Received: 28 June 2011
Accepted: 8 August 2011

Abstract

By large-scale Monte Carlo simulations of semiflexible polymers in d=2 dimensions the applicability of the Kratky-Porod model is tested. This model is widely used as “standard model” for describing conformations and force vs. extension curves of stiff polymers. It is shown that semiflexible polymers in d=2 show a crossover from hard rods to self-avoiding walks, the intermediate Gaussian regime (implied by the Kratky-Porod model) is completely absent. Hence the latter can also describe force vs. extension curves only if the contour length is only a few times larger than the persistence length. Consequences for experiments on biopolymers at interfaces are briefly discussed.