THEORY OF DIFFUSION-CONTROLLED REACTIONS IN POLYMERS UNDER FLOW

We extend the theoretical framework of de Gennes for treating diffusio n-controlled reactions in complex fluid systems to situations in which a steady, linear flow is externally imposed. Consideration is restric ted to systems that are dilute in reactive sites and for which the rea ction occurs instantaneously and irreversibly when a pair of sites are brought in close contact. Illustrative calculations are presented for the long-time intermolecular trapping rate constant in polymer melts where a small fraction of chains have a single terminally attached rea ctive group. Both shear and extensional flows are considered, as well as Rouse and reptation models of chain dynamics. Extensions of the ana lysis may have applications in modeling free radical termination proce sses and reactive blending.