Bond kinetics in simulated telechelic associating polymer networks

摘要

Telechelic associating polymers are simulated using a novel hybrid molecular dynamics (MD)/Monte Carlo (MC) algorithm. Within the simulation functionalised end groups, at both ends of the polymer chain, form reversible bonds according to MC rules, while the spatial positions of the polymers are dictated by MD. We study the kinetics of the MC process. From the observed rates of breakage and formation, the aggregate size distribution can be obtained using a master equation. These distributions are in agreement with those obtained directly from the simulation data. We report on the system at rest, under uniform shear, and under oscillatory shear. The rates provide insight in the dynamics of the system at a microscopic level. We found that in all cases formation is dominated by small aggregates of size 1-5 joining bigger ones, whereas dissociation is dominated by aggregates of sizes 45-55 breaking in two approximately equal halves. This work complements experiment, which can only access certain microscopic quantities, like aggregate size distribution, but not reaction rates such as those reported in this manuscript.