Issue 5, 2008

Effect of substrate adhesion and hydrophobicity on hydrogel friction

Abstract

In this paper, the frictional behavior of a neutral hydrogel, polyvinyl alcohol (PVA), on smooth solid substrates with various levels of hydrophobicity have been investigated in water using a strain-controlled parallel-plate rheometer. For the sliding velocity dependence of friction, we detected a distinct friction transition on hydrophobic substrates that are strongly adhesive to the gel, while no clear transition was observed on hydrophilic substrates that are weakly adhesive to the gel. Even on the most hydrophobic substrate, the maximum frictional stress is approximately 1/10–1/5 of the gel’s elastic modulus under a large normal strain of 26%. Furthermore, the frictional stress on hydrophobic substrates in the high velocity region, larger than the transition, is much lower than that on hydrophilic ones. We attempted to explain these phenomena with the help of two models: a molecular model based on the thermal fluctuations occurring during adsorption–desorption of polymers and a continuum mechanics model based on elastic dewetting and forced wetting.

Graphical abstract: Effect of substrate adhesion and hydrophobicity on hydrogel friction

Article information

Article type
Paper
Submitted
29 Oct 2007
Accepted
28 Jan 2008
First published
04 Mar 2008

Soft Matter, 2008,4, 1033-1040

Effect of substrate adhesion and hydrophobicity on hydrogel friction

T. Tominaga, N. Takedomi, H. Biederman, H. Furukawa, Y. Osada and J. P. Gong, Soft Matter, 2008, 4, 1033 DOI: 10.1039/B716465C

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements