When a polymer is modeled by a long elastic rod of homogeneous and isotropic material, we find that its persistence length is proportional to the cube of the critical length for Euler buckling caused by the root-mean-square contraction force. The proportionality constant involves the radius of the circular cross section of the rod. For paramyosin, the persistence length is larger than the critical buckling length by a factor of about 3.

• Received 22 July 1986

DOI:https://doi.org/10.1103/PhysRevA.34.4467