Evidence for diffusion-controlled recombination kinetics in model wormlike micellesJ. T. Padding1, 2 and E. S. Boek1
1 Schlumberger Cambridge Research, High Cross Madingley Road, Cambridge CB3 0EL, UK
2 Department of Chemistry, University of Cambridge Lensfield Road, Cambridge CB2 1EW, UK
(Received 19 December 2003; accepted in final form 24 March 2004)
We study the recombination kinetics and stress relaxation in a generic reversible polymer model, which is believed to resemble a wormlike micellar system. We find evidence that, at high concentrations, the recombination kinetics in this model cannot be described by a mean-field approach, but is diffusion-controlled and dominated by self-recombination events. We observe that the long-time stress relaxation of unentangled chains is proportional to , with a relaxation time given by , where th is the average diffusion time to a different chain end, and is the characteristic relaxation time of a system of "dead" polymers of length equal to the average micellar length. A recombination activation barrier is needed to drive the system towards mean-field behaviour. This, in its turn, is often required in order to realistically model the rheology and dynamics of wormlike micelles.
82.20.Wt - Computational modeling; simulation.
83.80.Qr - Surfactant and micellar systems, associated polymers.
© EDP Sciences 2004