Free expansion of elastic filaments

The dynamics of an elastic polymer filament undergoing contour length expansion is studied using computer simulation. The expansion occurs by development of transverse buckling waves that grow through a coarsening process. The growing buckles locally organize into a helical structure with a characteristic persistence length. The helical domain boundaries are eliminated from the relaxing structure by unwinding through the ends of the rod. The growth of the helical domains results in self-propulsive motion of the expanding rod, as one large helix spanning the entire chain relaxes during the late stages of the dynamics. Stability analyses and scaling arguments are provided to explain the simulation results.