Sedimentation Constants of Broken Chains and Wormlike Coils

Abstract

The sedimentation constant of two stiff-chain models has been calculated by the method of Kirkwood. The broken chain consists of straight rigid segments of equal length connected by universal joints. The wormlike chain is that described by Kratky and Porod. In the limit of large contour length, both models have the same slope in a plot of S against n½, where n is the number of straight segments in the one case and the number of Kuhn statistical lengths in the other. The intercept of this plot at n=0 is sensitive to the model chosen as well as to the chain diameter and the statistical segment length.