Mesostructure of polymer collapse and fractal smoothing

We investigate the internal structure of a polymer during collapse from an expanded coil to a compact globule. Collapse is more probable in local regi ons of high curvature, so a smoothing of the fractal polymer structure occu rs that proceeds systematically from the shortest to the longest length sca les. A proposed universal scaling relationship is tested by comparison with Monte Carlo simulations. We speculate that the universal form applies to v arious fractal systems with local processes that promote smoothness over ti me. The results complement earlier work showing that on the macroscale poly mer collapse proceeds by driven diffusion of the polymer ends. [S1063-651X( 99)01209-X].