Renewable Photosensitive Castor Oil to Fabricate Ionogels: Freezing-Tolerance, Stretchability, and Degradation for 3D Printing and Flexible Sensor Applications

Abstract

With the escalating demands for sustainability in flexible sensing materials, the development of a novel, environmentally friendly, and multifunctional ionogel utilizing bio-based raw materials has become paramount. However, castor oil with abundant modified sites and natural flexible long carbon chain structure, is rarely explored in the context of ionogels. Here a novel approach is proposed to fabricate high-performance ionogels through rapid photopolymerization of photosensitive modified acrylate-based castor oil (ACO) with ACMO (acrylomorpholine), and [Mim-BS] [HSO₄] (1-sulfobutyl-3-methylimidazolium hydrogen sulfate). Herein, ACO not only participates in the photochemical crosslinking of the ionogel but also imparts exceptional stretchability to the ionogel due to its flexible structure. By modulating the content of acrylate-based castor oil, the transparency, conductivity, and mechanical properties of the ionogel can be significantly enhanced. Furthermore, the ionogel incorporating a bio-sourced component (castor oil) obtained through this photochemical crosslinking process enables high-precision 3D printing and demonstrates remarkable degradability, low-temperature resistance, excellent self-healing capabilities, and sensing performance. These findings provide new perspectives for the design of green ionogels and beyond.