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

Area of Science:

• Materials Science
• Mechanics of Materials
• Polymer Science

Background:

• Polymer gels are porous, fluid-saturated materials susceptible to swelling/shrinking.
• Stimuli-induced deformation can generate significant stresses, potentially causing material failure.
• Understanding stress and deformation in constrained polymer gels is critical for their application and integrity.

Purpose of the Study:

• To investigate stress and deformation in hydrated constrained polymer gels under varying chemical potential.
• To develop and apply a nonlinear stress-diffusion model for analyzing chemo-mechanical behavior.
• To extend classical poroelastic theory to account for prestressed configurations in polymer gels.

Main Methods:

• A nonlinear stress-diffusion model was employed for chemo-mechanical analysis.
• Two distinct elastic constraint configurations were analyzed: thickness and plane constraints.
• An incremental analysis was performed on a prestressed configuration.

Main Results:

• The model successfully analyzes stress and deformation in hydrated constrained polymer gels.
• The derived model extends linear poroelastic theory to prestressed conditions.
• Analytical results were compared with existing literature for validation.

Conclusions:

• The developed nonlinear model accurately predicts the behavior of constrained polymer gels.
• The inclusion of prestressed configurations is essential for realistic gel behavior analysis.
• The model provides a valuable tool for understanding and predicting polymer gel failure.