Molecular transport and flow of polymers on polymer brushes and deformable surfaces: Computer simulation of model systems

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The flow of a polymer liquid, spreading of droplets and their motion under the influence of an external force on one- and two-component polymer brushes will be studied by computer simulations of a coarse-grained polymer model. Different simulation techniques will be employed to obtain the viscosity of the liquid, the flow field in the vicinity of the polymer substrate, the equilibrium and advancing contact angles, and the contact angle hysteresis. The motion of the three-phase contact line, the deformation of the soft substrate (polymer brush) in its vicinity, and mechanisms of energy dissipation shall be investigated as a function of the grafting density of the polymer brush. The simulation results will be compared quantitatively to phenomenological and continuum/hydrodynamical theories and those approaches shall be employed to extrapolate from nanoscopic-sized droplet in the simulations to experimentally relevant sizes. In a second step we will consider laterally structured substrates (chemical stripes or binary polymer brushes, which exhibit microphase separation) and investigate the motion and pinning of the contact line by the lateral structure. A close connection to experiments of droplet motion on soft substrates and meso-scale, continuum description of flow shall be established.