This is an abstract for a presentation given at the Seventh Foresight Conference on Molecular Nanotechnology . There will be a link from here to the full article when it is available on the web. The shear response of polymer brushes is important in a variety of applications, including colloidal stabilization and lubrication.
Polymer brushes consist of flexible polymer chains terminally anchored at surfaces.
Klein et al. 1 demonstrated that a pair of opposing brushes, when slid past one another in the presence of a good solvent, experience a repulsive normal force and interpreted this as brush swelling under shear. The origin of this shear induced swelling is not well understood, although several analytic theories based on scaling arguments and hydrodynamic models have been proposed 2,3 . The brush senses the shear force, responds by swelling, and thereby readjusts the shear and flow to maintain a constant flow rate. To explore the mechanism of shear induced swelling, molecular dynamics simulations of two opposing polymer brushes immersed in a good solvent have been carried out under shear.