Self-Healing, Remoldable, and Conductive Starch-Based Dual Reversible Cross-Linking Hydrogels for Strain Sensors

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Polysaccharide hydrogels are promising for flexible strain sensors due to sustainability.
• Manufacturing complexity and mechanical degradation limit their use.
• Reversible bond chemistry can enable self-healing properties.

Purpose of the Study:

• To develop a self-healing, conductive hydrogel for wearable sensors.
• To improve the mechanical properties and lifespan of polysaccharide-based hydrogels.
• To explore the use of cellulose nanocrystals in hydrogel fabrication.

Main Methods:

• Fabrication of a starch-based conductive hydrogel using borax cross-linking.
• Incorporation of poly(vinyl alcohol) (PVA) and cellulose nanocrystals (CNCs).
• Characterization of mechanical properties, self-healing ability, and electrical conductivity.

Main Results:

• The hydrogel exhibited enhanced strength and self-healing due to dual reversible cross-links from CNCs.
• Sodium and borate ions improved electrical conductivity and strain sensitivity.
• The material showed potential for wearable sensors monitoring human movement and communication.

Conclusions:

• Starch-based hydrogels with PVA and CNCs offer a straightforward route to self-healing and conductive materials.
• The hydrogel's remoldability at room temperature enhances practical applicability.
• This work advances sustainable wearable sensor technologies using renewable resources.