Polymer brush collapse under shear flow

Abstract

Shear responsive surfaces offer potential advances in a number of applications. Surface functionalisation using polymer brushes is one route to such properties, particularly in the case of entangled polymers. We report on neutron reflectometry measurements of polymer brushes in entangled polymer solutions performed under controlled shear, as well as coarse-grained computer simulations corresponding to these interfaces. Here we show a reversible and reproducible collapse of the brushes, increasing with the shear rate. Using two brushes of greatly different chain lengths and grafting densities, we demonstrate that the dynamics responsible for the structural change of the brush are governed by the free chains in solution rather than the brush itself, within the range of parameters examined. The phenomenon of the brush collapse could find applications in the tailoring of nanosensors, and as a way to dynamically control surface friction and adhesion.

References in corpus (7)

• Accurate effective pair potentials for polymer solutions
• Static and dynamic properties of the interface between a polymer brush and a melt of identical chains
• Cyclic motion and inversion of surface flow direction in a dense polymer brush under shear
• Combined neutron reflectometry and rheology
• Arm retraction dynamics in dense polymer brushes
• Simulation of Entangled Polymer Solutions
• Simulating confined particles with a flat density profile

Cited by in corpus (6)

• Entanglement reduction induced by geometrical confinement in polymer thin films
• Shear deformation of low-density polymer brushes in a good solvent
• Dynamical structure of entangled polymers simulated under shear flow
• The viscoelastic signature underpinning polymer deformation under shear flow
• 5D Entanglement in Star Polymer Dynamics
• Near surface concentration profile of sheared semi-dilute polymer solutions