Cellulose nanofibril-enhanced strong ionic gel with dynamic hydrogen bonds for cryogenic and dehydration-resistant tactile sensing

Abstract

The growing demand for high-performance tactile sensors in flexible electronics, such as electronic skins, robots, and wearable devices, has highlighted the need for robust ionic conductors. While traditional hydrogels, organogels, and ionogels are commonly used, their performance is often compromised under extreme conditions like freezing and dehydration. Here, we present a hydrogen bonds reinforced ionic gel, synthesized via a simple casting process using polyvinyl alcohol (PVA), cellulose nanofibril (CNF), and phytic acid (PA) (PVA-CNF-PA gels). The ionic gel demonstrates superior ionic conductivity (0.352 S m⁻¹), exceptional stretchability (860 % elongation at break), strong (up to 36.4 MPa), and remarkable environmental stability. Notably, it maintains 0.161 S m⁻¹ conductivity at −20 °C and >99 % mass retention after 120 days in ambient conditions. When integrated into supercapacitive pressure sensors, PCPGs exhibits a broad sensing range (20 Pa-400 kPa) and high sensitivity (3.5 MPa⁻¹), functioning reliably under harsh environmental conditions. These findings position PVA-CNF-PA gels as a promising material for next-generation flexible sensors and ionic conductors.