Nonlinear Viscoelasticity of and Structural Modulation in Guar Gum-Enhanced Triple-Network Hydrogels

Area of Science:

• Materials Science
• Polymer Science
• Biomaterials Engineering

Background:

• Thermo-responsive hydrogels are advanced materials with tunable properties.
• Polyvinyl alcohol (PVA) based hydrogels offer biocompatibility and versatility.
• Incorporating specific additives can significantly enhance hydrogel performance.

Purpose of the Study:

• To investigate the impact of guar gum on the properties of a thermo-responsive triple-network hydrogel.
• To determine the optimal concentration of guar gum for enhanced hydrogel performance.
• To analyze the structural, mechanical, and viscoelastic changes induced by guar gum.

Main Methods:

• Synthesis of PVA/TA/PVA-MA-g-PNIPAAm hydrogels with varying guar gum concentrations (0-0.75 wt%).
• Characterization using large-amplitude oscillatory shear (LAOS), SEM imaging, XRD, and mechanical testing.
• Evaluation of thermal response and dimensional stability under thermal cycling.

Main Results:

• Guar gum incorporation increased hydrogel crystallinity and induced strain hardening.
• Optimal mechanical properties, including shear-thickening (40% increase) and high elongation to break (500%), were achieved at 0.5 wt% guar gum.
• The hydrogel with 0.5 wt% guar gum demonstrated excellent thermal response and stability.

Conclusions:

• Guar gum is an effective additive for enhancing the mechanical robustness and thermal properties of thermo-responsive hydrogels.
• The concentration of guar gum is critical; higher amounts can lead to reduced structural resilience and brittleness.
• The optimized hydrogel shows potential for applications requiring tunable mechanical and thermal behaviors.