Simulation study of a two-dimensional system of semiflexible polymers

We report computer simulations of a two-dimensional system of semiflexible polymers consisting of infinitesimally thin hard segments connected by joints of variable flexibility. As the density is increased, we observe a transition from the isotropic phase to a "nematic" phase with quasi-long-range orientational order. This transition appears to be of the Kosterlitz-Thouless type. We observe that, whereas at low densities the most rigid polymers have the lowest compressibility, the opposite is true at high densities. We argue that such behavior is to be expected. Finally, we study the scaling behavior of the elastic constants for splay and bend in the nematic phase and find good agreement with the relevant theoretical predictions.