The behavior of polymer chains adsorbed on surfaces has been well studied by simulations and theory. Such substrates are usually represented by atomistically or perfectly smooth models. However, realistic surfaces display both physical and chemical inhomogeneities, leading to complexities in the equilibration and sampling of such systems. We focus here on the effect of physical asperities on adsorption, and investigate the mechanisms governing polymer surface interactions via molecular simulations. Monte Carlo simulations are employed to study polymer adsorption on self-affine (fractally rough) substrates. The influence of surface fractal dimension and amplitude are explored for adsorbates of different molecular weights and molecular weight distributions by investigating monomer-surface interactions, density profiles, distributions of adsorbed chain fractions and chain topologies. The effect of uniform roughness is studied via Molecular Dynamics simulations. Substrates of different wavelengths are generated using 3-D sinusoidal profiles, for adsorbates of varying chain lengths. Our results reveal that polymer adsorption can be controlled solely by manipulating entropic factors such as physical heterogeneities in the underlying substrates. In contrast to traditional polymer thermodynamics, we show how short chains are preferentially attached in comparison to longer chains by changing surface roughness.

Molecular simulation of polymer adsorption on rough surfaces

249th National Meeting (2015)

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