Figure 6.

Although (top) the extent to which viscosity decelerates end-to-end collision rates (the slopes from Fig. 5) is strongly length dependent, (bottom) the intercepts of the viscosity versus rate relationship are largely independent of polymer length. The length dependence of the slopes is effectively indistinguishable from the length dependence observed for the end-to-end collision rate (the solid line represents a power-law fit with an exponent of 3.85 ± 0.93), presumably because the longer diffusion length scales of longer polymers leads to a greater sensitivity to solvent viscosity. The origins of the much weaker dependence of the intercepts on chain length is less clear, but may reflect cancellation between the length dependencies of the end-to-end approach probability and internal friction within the chain (see text).