Transparent, Antifreezing, Ionic Conductive Cellulose Hydrogel with Stable Sensitivity at Subzero Temperature

Area of Science:

• Materials Science
• Polymer Chemistry

Background:

• Cellulose is a sustainable biopolymer with potential for advanced material applications.
• Developing functional hydrogels with ionic conductivity and environmental stability remains a challenge.

Purpose of the Study:

• To fabricate transparent, ionic conductive cellulose hydrogels (CCHs) with inherent antifreezing properties.
• To investigate the thermal stability and mechanical properties of the developed CCHs.
• To evaluate the sensing performance of CCH-based devices for strain, pressure, and temperature.

Main Methods:

• Dissolving cellulose in an aqueous benzyltrimethyl ammonium hydroxide (BzMe3NOH) solution.
• Direct fabrication of hydrogels via chemical cross-linking without post-treatment.
• Characterization of transparency, mechanical properties, and ionic conductivity over a wide temperature range (-27.8 to 62.1 °C).
• Testing of CCH-based sensor performance under tensile strain, compressive pressure, and temperature variations.

Main Results:

• Successfully synthesized transparent CCHs with over 90% transparency.
• Demonstrated stable mechanical properties and ionic conductivity from -27.8 °C to 62.1 °C.
• CCH-based sensors showed stable and sensitive responses to strain, pressure, and temperature with fast response times and minimal hysteresis, even at subzero temperatures.

Conclusions:

• Benzyltrimethyl ammonium hydroxide facilitates the direct fabrication of antifreezing, ionic conductive cellulose hydrogels.
• The developed CCHs exhibit excellent thermal stability, transparency, and multifunctional sensing capabilities.
• This work presents a sustainable and simple method for creating advanced cellulose-based soft conductors for diverse applications.