A self-healing and recyclable carrageenan based gel based on multi-dynamic interactions for multifunctional sensor

Preparation of high performance and recyclable gels remain a challenge. In this study, a zwitterionic ion poly-[2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl) ammonium hydroxide (PDMAPS) network was constructed in renewable polysaccharide carrageenan to obtain CMM gel. The multiple reversible cross-linking network in CMM gel was engineered by molecular-level multi-dynamic interactions including hydrogen bonds among the molecular chains, two-dimensional MXene and tannic acid (TA), as well as electrostatic interaction. CMM gels exhibited enhanced mechanical strain (~1880%), low-temperature resistance, self-healing performance (~95%), recyclable property, and antibacterial ability. CMM gel can be directly served as a strain sensor with short responsive time to accurately discern subtle and macro bodily motions, handwriting and personal physiological state, even after self-healing and recycling. Additionally, CMM gel can be used as solid electrolyte with polyaniline(PANI) on both sides to obtain sandwich structure CMM-PANI gel, which can be fabricated as all-solid state capacitor with high area specific capacitance of 478 mF/cm2 at 2mA/cm2. Furthermore, a self-powered sensing device was assembled by the combination of the CMM gel and the capacitor, which demonstrates the sensing performance on various physical activities. This study gives an essential strategy for designing and fabricating self-healing and recyclable gels, and opens up new avenues for the practical application of gels.