Fully Water-Soluble, High-Performance Transient Sensors on a Versatile Galactomannan Substrate Derived from the Endosperm.

Green electronics on biodegradable substrates from natural sources have gained broad interest because of the advantages of being biodegradable, recyclable, sustainable, and cost-efficient. This study presents a low-cost, yet simple extraction and purification method that explores aqueous extraction and precipitation with ethanol for the synthesis of galactomannan films. In salient contrast to the other materials of natural origin, the process to obtain galactomannan films is energy efficient and environmentally friendly. As an alternative biodegradable material, galactomannan has direct relevance to the recent emerging biodegradable or transient electronics. The galactomannan substrate with temperature sensors and electrodes fabricated from zinc, a biodegradable material noted for its essential biological function, demonstrates a high-precision measurement of temperature and high-fidelity monitoring of electrophysiological signals (electromyogram or electrocardiogram). The resulting disposable sensors disappear without a trace in water and produce environmentally benign end products that could even be used for alkaline soil amendments. The set of materials explored in this study is also stable in organic solutions, enabling solvent-based fabrication that may be combined with recent advances in additive manufacturing techniques for a novel manufacturing method.