A spider silk-inspired, transparent, anti-freezing ionic conductive hydrogel as a flexible sensor device

Area of Science:

• Materials Science
• Polymer Chemistry
• Nanotechnology

Background:

• Ionically conductive hydrogels are crucial for flexible electronics but face challenges in low-temperature performance and transparency.
• Designing functional hydrogel structures for diverse applications remains a significant hurdle.

Purpose of the Study:

• To develop an antibacterial and ionically conductive hydrogel with high transparency and robust mechanical properties.
• To explore its potential in low-temperature sensing and flexible electronic devices.

Main Methods:

• Fabrication of TEMPO-oxidized cellulose nanofiber/polyvinyl alcohol/quaternary ammonium chitosan/Al3+ (CPQA-EH) hydrogel via solution mixing and immersion.
• Utilizing organic solvent-induced in situ phase separation and crystallization to form a nano-fishnet structure.
• Characterization of ionic conductivity, transparency, mechanical strength, toughness, and low-temperature sensing capabilities.

Main Results:

• Achieved an ionically conductive hydrogel (CPQA-EH) with 7.50 ms cm-1 conductivity and 93.7% transparency.
• Demonstrated excellent tensile strength (1341.86 kPa) and toughness (6992.53 kJ m-3).
• Exhibited reliable low-temperature sensing down to -80 °C and sensitive detection of strain and pressure.

Conclusions:

• The developed CPQA-EH hydrogel offers a promising solution for advanced flexible electronics, particularly in extreme environments.
• Its unique properties enable applications in wearable sensors for human motion and vocalization detection, and as transparent display devices.