Deviations from dynamic dilution in the terminal relaxation of star polymers - art. no. 195502

We present a "slip-link" model for relaxation of entangled star polymers th at accounts for chain-end fluctuations and constraint release and that expl ains deviations from the "dynamic dilution" equation observed in recent die lectric and stress relaxation data. In the terminal regime where tube expan sion fails to keep up with chain relaxation, relaxation is controlled by ra re events in which newly created entanglements near the branch point draw t he chain end towards the last remaining old entanglement, where a shallow f luctuation releases it.