Eco-designed cellulose-reinforced deep eutectic gels with synergistic mechanical strength, ionic conductivity, and freezing tolerance for flexible electronics

Abstract

Growing interest in flexible electronics is driving the development of deep eutectic gels that combine mechanical adaptability, electrical functionality, and environmental sustainability; however, achieving these properties simultaneously remains challenging. Herein, we propose an eco-designed DEG system reinforced with sugarcane bagasse cellulose, where a three-component choline chloride/acrylic acid/glycerol (ChCl/AA/Gly) deep eutectic solvent (DES) serves simultaneously as a cellulose-processing medium and a polymerization precursor. Owing to the acidity of AA and the strong hydrogen bonding network within the DES, raw bagasse cellulose is directly hydrolyzed into micron-scale cellulose fibers and uniformly dispersed, avoiding harsh pretreatments. Within the gel, ChCl provides mobile ions, AA forms a rigid skeleton, Gly enhances flexibility and ion mobility, and cellulose fibers reinforce the matrix through strong hydrogen bonding. The resulting gels exhibit enhanced tensile strength, broad adhesion capability, favorable ionic conductivity (12.7 mS cm⁻¹ at room temperature), and outstanding freezing tolerance (down to –50 °C). These properties enable versatile applications as flexible strain sensors and supercapacitor electrolytes, delivering a high gauge factor (10.17) and durable cycling stability over 20 000 cycles. This study presents a facile strategy for constructing cellulose-reinforced multi-component eutectic gels, offering a sustainable pathway for advanced flexible electronic materials.