Repository logo
 

Wrinkling instabilities of swelling hydrogels

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Worster, M Grae 

Abstract

We investigate the formation of wrinkling instabilities at the interface between layers of hydrogel and water, which arise to relieve horizontal compressive stresses caused by either differential swelling or confinement. Modelling the gel using a linear-elastic-nonlinear-swelling approach, we determine both a criterion for marginal stability and the growth rates of normal modes. Furthermore, our formalism allows us to understand the influence of differential swelling on the stability of hydrogels brought into contact with water, and we find three distinct phases of the instability. Initially, when only a thin skin layer of gel has swollen, buckles grow rapidly and the gel deforms as an incompressible material. A balance between normal elastic stress and pore pressure selects a wavelength for these buckles that increases with the square root of time. At late times, when the gel approaches a uniformly-swollen state, buckles can only grow by differential swelling, on much slower timescales determined by solvent transport. At intermediate times, growth is driven by the same fluid transport process as at late times but gradients in fluid pressure in the gel as it swells destabilise the interface, driving faster growth of wrinkles. We also explain why some instabilities can be transient, 'healing' as time progresses, whilst others must remain for all time.

Description

Keywords

Journal Title

Physical Review E: Statistical, Nonlinear, and Soft Matter Physics

Conference Name

Journal ISSN

2470-0045
2470-0053

Volume Title

Publisher

American Physical Society
Sponsorship
NERC (2436164)

Version History

Now showing 1 - 2 of 2
VersionDateSummary
2024-04-10 08:36:55
Published version added
1*
2024-03-26 00:30:36
* Selected version