Kinetics and dynamics of wormlike micelles under shear

Mimicking giant cylindrical micelles in solution, self-assembled linear polymers are studied by Langevin dynamics in shear flow. The kinetics of chain scission (with rate ks per bond) and chain end recombination (with rate kr) is modelled by associating to each monomer two arms for binding. A switch of pair potentials (from bounded to unbounded or vice versa) is tried with a fixed attempt frequency per arm ω modelling the effect of a potential barrier along a reaction path. The opening of a selected bond or the bonding between two selected free ends are accepted or not according to a Monte Carlo algorithm. We are interested in the coupled effects of the shear flow and the scission-recombination kinetics on the structural and rheological properties of this micellar system. Our study is performed in semi-dilute and dynamically unentangled regime conditions with an average chain size L 0. The explored ω range is chosen sufficiently high for the lifetime of the average size chain to remain shorter than its intrinsic (Rouse) longest relaxation time τR=τ0L0 2. Central to our analysis is the concept of dynamical unit of size Λ=(τ0ks)- 1/3