How Things Get Stuck: Kinetics, Elastohydrodynamics, and Soft Adhesion

Madhav Mani, Arvind Gopinath, and L. Mahadevan

Phys. Rev. Lett. 108, 226104 – Published 30 May 2012

Abstract

We consider the sticking of a fluid-immersed colloidal particle with a substrate coated by polymeric tethers, a model for soft, wet adhesion in many natural and artificial systems. Our theory accounts for the kinetics of binding, the elasticity of the tethers, and the hydrodynamics of fluid drainage between the colloid and the substrate, characterized by three dimensionless parameters: the ratio of the viscous drainage time to the kinetics of binding, the ratio of elastic to thermal energies, and the size of the particle relative to the height of the polymer brush. For typical experimental parameters and discrete families of tethers, we find that adhesion proceeds via punctuated steps, where rapid transitions to increasingly bound states are separated by slow aging transients, consistent with recent observations. Our results also suggest that the bound particle is susceptible to fluctuation-driven instabilities parallel to the substrate.

Received 13 December 2011

DOI:https://doi.org/10.1103/PhysRevLett.108.226104

Authors & Affiliations

Madhav Mani^1,*, Arvind Gopinath², and L. Mahadevan^1,3,†

¹School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
²Martin Fisher School of Physics, Brandeis University, Waltham, Massachusetts 02453, USA
³Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA

^*Present address: KITP and UCSB Physics, Santa Barbara, CA, USA.
^†Corresponding author. lm@seas.harvard.edu