Swelling and shrinking in prestressed polymer gels: an incremental stress–diffusion analysis

• Published in: Proceedings of the Royal Society. A, Mathematical, physical, and engineering sciences Vol. 475; no. 2230; p. 20190174
• Main Authors: Rossi, Marco, Nardinocchi, Paola, Wallmersperger, Thomas
• Format: Journal Article
• Language: English
• Published: The Royal Society Publishing 01.10.2019
• ISSN: 1364-5021; 1471-2946
• DOI: 10.1098/rspa.2019.0174

Polymer gels are porous fluid-saturated materials which can swell or shrink triggered by various stimuli. The swelling/shrinking-induced deformation can generate large stresses which may lead to the failure of the material. In the present research, a nonlinear stress–diffusion model is employed to investigate the stress and the deformation state arising in hydrated constrained polymer gels when subject to a varying chemical potential. Two different constraint configurations are taken into account: (i) elastic constraint along the thickness direction and (ii) plane elastic constraint. The first step entirely defines a compressed/tensed configuration. From there, an incremental chemo-mechanical analysis is presented. The derived model extends the classical linear poroelastic theory with respect to a prestressed configuration. Finally, the comparison between the analytical results obtained by the proposed model and a particular problem already discussed in literature for a stress-free gel membrane (one-dimensional test case) will highlight the relevance of the derived model.