Single-polymer adsorption in shear: Flattening vs. hydrodynamic lift and surface potential corrugation effects
Physics Department, TU Munich - 85748 Garching, Germany, EU
Accepted: 25 October 2010
The adsorption of a single polymer to a flat surface in shear is investigated using Brownian hydrodynamics simulations and scaling arguments. Competing effects are disentangled: in the absence of hydrodynamic interactions, shear drag flattens the chain and thus enhances adsorption. Hydrodynamic lift on the other hand gives rise to long-ranged repulsion from the surface which preempts the surface-adsorbed state via a discontinuous desorption transition, in agreement with theoretical arguments. Chain flattening is dominated by hydrodynamic lift, so overall, shear flow weakens the adsorption of flexible polymers. Surface friction due to small-wavelength surface potential corrugations is argued to weaken the surface attraction as well.
PACS: 82.35.Gh – Polymers on surfaces; adhesion / 83.50.-v – Deformation and flow / 82.37.Gk – STM and AFM manipulations of a single molecule
© EPLA, 2010