Predicting reaction behavior of tethered polymers in shear flow

Kinetics of force-mediated chemical reactions of end-tethered polymers with varying chain length N in varying shear rate flow gamma are explored via coarse-grained Brownian dynamics simulations. At fixed gamma , force F along a polymer increases linearly with N as previously predicted; however, contrary to existing theory, the F(N) slope increases for N above a transition length that exhibits minimal dependence on gamma . Force profiles are used in a stochastic model of a force-mediated reaction to compute the time for x percent of a polymer population to experience a reaction, t(x). Observations are insensitive to the selected value of x in that t(x) data for varying N and gamma can be consistently collapsed onto a single curve via appropriate scaling, with one master curve for systems below the transition N (small N) and another for those above (large N). Different force scaling for small and large N results in orders of magnitude difference in force-mediated reaction kinetics as represented by the population response time. Data presented illustrate the possibility of designing mechano-reactive polymer populations with highly controlled response to flow across a range in gamma