WORMLIKE CHAINS NEAR THE ROD LIMIT - TRANSLATIONAL FRICTION COEFFICIENT

The translational friction coefficient, E, of the Kratky-Porod (KP) wormlike chain near the rod limit is calculated according to the Yamakawa-Fujii formulation of the Oseen-Burgers method, with a wormlike sausage model assumed for the chain. Here wormlike sausage means a wormlike cylinder capped with hemispheres at its ends. The resulting expression for E converges to the Stokes law at the limit of L = d, where L is the contour length and d is the diameter of the sausage. Its comparison with the Yamakawa-Fujii expression, which ignores end effects, shows that end corrections to E are unexpectedly small. In fact, the Yamakawa-Fujii theory is accurate down to as short a chain as L/d ~ 4. © 1979, American Chemical Society. All rights reserved.