Smart Organogels with Antiswelling, Strong Adhesion, and Freeze-Tolerance for Multi-Environmental Wearable Bioelectronic Devices

Abstract

Gel-based wearable bioelectronic devices have garnered increasing attention due to their unique properties. However, developing multiple environmentally tolerant (resistant to freezing, drying, and various solvents) conductive gels presents a formidable challenge. Herein, we designed and developed a smart organogel exhibiting high stretchability (up to 550% strain and 19.3 kPa modulus), adhesion (24.8 kPa on pigskin), and resistance to freezing, drying, and various solvents. This achievement is attributed to the synergistic effects arising from the interplay between hydrophobic and hydrophilic polymer segments, the multiple bond interactions within a composite network, and the robust adhesion provided by catechol functional groups in binary solvent dispersion. Furthermore, after introducing hydroxyl-functionalized carbon nanotubes (CNTs) into the network, the organogels demonstrate high conductivity with satisfactory sensitivity (GF = 3.68), wide strain range (0.5−450%), and prominent signal stability. Meanwhile, benefiting from the nonswelling and antifreezing attributes, the obtained conductive organogel proves its versatility as an all-weather sensor. It can achieve accurate and reliable strain sensing in a wide temperature range of −20 to 50 °C and exhibits a high-precision Morse code to transmit information underwater. Moreover, it could also serve as soft bionic electrodes to integrate into a wearable wireless device for detecting human physiological signals underwater. This study provides an effective and versatile design strategy for developing future advanced gel-based sensors and soft bioelectronic devices with robust tolerance to diverse environmental conditions.