Some comments on the second virial coefficient of semiflexible polymers

Abstract

A Monte Carlo study is made of the mean-square radius of gyration 〈 S2 〉 and second virial coefficient A2 for the two freely rotating chains with the Lennard-Jones (LJ) 6-12 potential and the hard-sphere (HS) one in the range of the bond angle θ from 109° (typical flexible chain) to 175° (typical semiflexible or stiff chain) and in the range of the number n of bonds from 6 to 1000. It is shown that a value may be properly assigned to the collision diameter of the HS potential so that 〈 S2 〉 of the chain with the HS potential agrees well with that of the chain with the LJ one whose parameter values correspond to a good-solvent condition irrespective of the chain stiffness. It is then found that A2 of the latter chain becomes remarkably smaller than that of the former as the chain stiffness is increased. The result implies that the binary-cluster approximation does not seem to work well for typical semiflexible and stiff polymers. © 2008 American Institute of Physics.