Deviations from dynamic dilution in the terminal relaxation of star polymers.
We present a "slip-link" model for relaxation of entangled star polymers that accounts for chain-end fluctuations and constraint release and that explains deviations from the "dynamic dilution" equation observed in recent dielectric and stress relaxation data. In the terminal regime where tube expansion fails to keep up with chain relaxation, relaxation is controlled by rare events in which newly created entanglements near the branch point draw the chain end towards the last remaining old entanglement, where a shallow fluctuation releases it.
Shanbhag
S
S
Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109-2136, USA.
Larson
R G
RG
Takimoto
J
J
Doi
M
M