Quantitative Macromolecular Modeling Assay of Biopolymer-Based Hydrogels

Area of Science:

• Materials Science
• Polymer Science
• Biomechanics

Background:

• Rubber elasticity theory, typically for polymers, is extended to hydrogels.
• Hydrogels possess unique water content and viscoelastic properties not fully captured by idealistic models.
• Imperfections in polymer networks require advanced constitutive models for accurate description.

Purpose of the Study:

• To apply rubber elasticity constitutive models for hyperelastic parameter identification in hydrogels.
• To characterize hydrogel intrinsic properties and equilibrium swelling behavior.
• To determine the polymer-solvent interaction parameter and its relation to cross-linking.

Main Methods:

• Hyperelastic parameter identification using stress-strain response under compression.
• Swelling experiments to determine intrinsic properties (e.g., density) and equilibrium swelling.
• Application of swelling-equilibrium theory to calculate polymer-solvent interaction parameter.

Main Results:

• Average mesh size from rubber elasticity theory serves as a concentration-dependent characteristic length.
• Non-linear elastic response is coupled to viscoelasticity through hysteresis.
• Hysteresis quantifies energy dissipation in hydrogels during large deformations.

Conclusions:

• Rubber elasticity models, when enhanced, can effectively describe hydrogel mechanical behavior.
• Hydrogel network characteristics and viscoelasticity are intrinsically linked.
• This approach provides a quantitative measure of energy dissipation in hydrogels.