Cold-resistant, highly stretchable ionic conductive hydrogels for intelligent motion recognition in winter sports

Area of Science:

• Materials Science
• Polymer Chemistry
• Biomedical Engineering

Background:

• Conductive hydrogels are crucial for flexible wearable sensors due to their flexibility and conductivity.
• Traditional hydrogels suffer from poor mechanical strength, frost resistance, and microbial contamination, limiting their practical use.

Purpose of the Study:

• To develop multifunctional polyvinyl alcohol (PVA)/carboxymethyl cellulose (CMC)/poly(acrylamide-co-1-vinyl-3-butylimidazolium bromide) (P(AAm-co-VBIMBr)) (PCPAV) ionic conductive hydrogels.
• To enhance mechanical properties, conductivity, transparency, anti-freezing, and antibacterial capabilities for advanced sensor applications.

Main Methods:

• Synthesized PCPAV hydrogels via in situ free radical polymerization, incorporating a crosslinked P(AAm-co-VBIMBr) network into PVA/CMC.
• Utilized multiple polymer interactions (covalent, hydrogen bonding, electrostatic) to achieve desired material properties.

Main Results:

• Achieved high tensile strength (360.6 kPa) and elongation at break (810.6%) with good toughness and fatigue resistance.
• Demonstrated excellent transparency (~92%), high ionic conductivity (15.2 mS cm-1), antimicrobial activity, and sub-zero temperature performance.
• Exhibited a wide strain range (0-800%), high strain sensitivity (GF = 3.75), fast response, and long-term stability.

Conclusions:

• The developed PCPAV hydrogels possess superior mechanical, conductive, transparent, anti-freezing, and antibacterial properties.
• These hydrogels are suitable for detecting a wide range of movements, from large joint motions to minute muscle activities.
• PCPAV-based hydrogel sensors show significant potential for flexible electronics, including health monitoring, soft robotics, and human-machine interfaces.