Effect of Patch Size and Attraction Energy on Polymer Chain Adsorption in Slits Created by Opposing Patch-Patterned Surfaces

HD Liu and S Li and QH Yang and MB Luo, MACROMOLECULAR THEORY AND SIMULATIONS, 34, e00076 (2025).

DOI: 10.1002/mats.202500076

The adsorption behavior of a polymer chain within a slit composed of two patch-patterned surfaces is investigated using Langevin dynamics simulations. Each surface exhibits periodic attractive square patches (period d, size L, attraction energy epsilon(ps)), with a 0.5d misalignment between the two surfaces. The adsorption degree increases with L, while the mean number of occupied patches and the surface-parallel component of the mean square radius of gyration exhibit a complex dependence on L. We identify distinct adsorption regimes: a single-surface and single-patch adsorbed state for L > L-s, an upper-lower and multi-patch adsorbed state for L > L-m, and a complete adsorbed state for L > L-c. At weak epsilon(ps), the polymer chain adopts single-surface and single-patch adsorption for middle L and upper-lower and multi-patch adsorption for large L. Conversely, a strong epsilon(ps) promotes upper-lower and multi-patch adsorption for small L, and single-surface and single-patch adsorption as L increases. The adsorption degree increases monotonically to saturate with epsilon(ps), while initially increases and subsequently decays toward stability. Notably, first decreases, then increases, and finally decreases to stabilize as epsilon(ps) increases. These results highlight the role of patch geometry and interaction strength in governing polymer adsorption behavior.

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