Forced desorption of polymers from interfaces

Douglas B. Staple, Michael Geisler, Thorsten Hugel, Laurent Kreplak, Hans Jürgen Kreuzer

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

In the past decade it has become possible to directly measure the adsorption force of a polymer in contact with a solid surface using single-molecule force spectroscopy. A plateau force in the force-extension curve is often observed in systems of physisorbed or noncovalently bonded polymers. If a molecule is pulled quickly compared to internal relaxation, then nonequilibrium effects can be observed. Here we investigate these effects using statistical mechanical models and experiments with a spider silk polypeptide. We present evidence that most experiments showing plateau forces are done out of equilibrium. We find that the dominant nonequilibrium effect is that the detachment height hmax(υ) increases with pulling speed υ. Based on a nonequilibrium model within a master-equation approach, we show the sigmoidal dependence of the detachment height on the pulling speed of the cantilever, agreeing with experimental data on a spider silk polypeptide. We also show that the slope with which the plateau forces detach is given by the cantilever force constant in both theory and experiment.

Original languageEnglish
Article number013025
JournalNew Journal of Physics
Volume13
DOIs
Publication statusPublished - Jan 2011

ASJC Scopus Subject Areas

  • General Physics and Astronomy

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