Transport Properties of Wormlike Chains with Applications to Double Helical DNA and Carbon Nanotubes

Many extended threadlike polymeric structures (e.g., certain synthetic polymers, carbon nanotubes, double helical DNA, and certain polypeptides) exhibit a degree of chain-stiffness intermediate between the idealized rod and the random coil. Such structures can be reasonably well described by the wormlike chain model, and we apply our previously developed numerical path-integration method to determine both the intrinsic viscosity [η] and the friction coefficient f of wormlike chains. We have also determined finite-thickness contributions to the volume and the radius of gyration and developed approximants for [η] and f that should be useful in characterization work. Our results are compared to previous computations of [η] and f and the uncertainties of the various computational methods for calculating these transport properties are considered. Our results are also compared to experimental viscometric, sedimentation, and light scattering results for double helical DNA, where we obtain accurate fits by assuming a hydrodynamic diameter of d = 2.4 nm and a persistence length of a = 50 nm. Computations are also performed for a region of parameter space that should be useful in the characterization of carbon nanotubes.