Modeling Lubrication with Polymer Brushes
We apply a variation of a well-established molecular coarse-grained brush model [1,2,3]. The strength of using a coarse-grained description of polymers for the questions addressed in this work lies in the length and time-scales that can be accessed at moderate computational cost, compared with fully atomistic simulations, while still exploring the dynamical evolution of a brush system. It also has the advantage of being relatively free of assumptions compared to more macroscopic models, such as self-consistent mean-field theories.
The polymer brushes are represented by a set of semiflexible, linear multibead-spring model chains that exhibit excluded volume effects, and are permanently tethered to the substrate by one end. Using this approach we simulate permanently chemisorbed polymer chains on a substrate. This multibead-spring model, using a nonlinear force law (finitely extendable nonlinear elastic, FENE) for bonded interactions, is known to capture the physical behavior of polymer brushes [2,4].
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