Solvent-Free Fabrication of a Bioderived, Ultrastretchable, and Adhesive Supramolecular Ionic Conductor for Wearable Sensing

The development of high-performance elastomers that simultaneously mitigate the environmental impact of petroleum-based materials and avoid the leakage issues associated with conventional ionogels remains a significant challenge. Herein, we report a solvent-free supramolecular ionic conductor constructed from two bioderived small molecules, thioctic acid (TA) and potassium lactate (PL). Through a facile one-step thermal polymerization, a hierarchical dynamic network is established, consisting of dynamic covalent disulfide bonds and multisite hydrogen-bonding interactions. Importantly, the incorporation of PL induces the formation of ionic-hydrogen bond clusters, which provide kinetic stabilization against room-temperature depolymerization of poly(thioctic acid) (polyTA) by restricting segmental mobility, while simultaneously serving as sacrificial bonds for energy dissipation. As a result, the poly(thioctic acid-potassium lactate) (P(TA-PL)) ionic conductor exhibits an ultrahigh elongation at break of up to 7000% while maintaining structural integrity. Furthermore, the material demonstrates strong adhesion to diverse substrates (e.g., up to 258 kPa on wood), rapid autonomous self-healing, and closed-loop thermal recyclability. When integrated into flexible strain sensors, the ionic conductor exhibits a wide sensing range, stable signal response, and good cycling stability. These sensors enable reliable monitoring of both subtle finger motions and large-scale human movements, demonstrating the potential of this bioderived ionic conductor for sustainable wearable electronics and human-machine interfaces.