Tough, self-healing polyurethane with novel functionality for fully recoverable layered sensor arrays

Although extensive effort has been made on developing self-healing materials with superior durability, there still remain considerable limits in materials and processes for acquiring fully self-healing integrated electronic devices. We report on the synthesis of novel oxime-carbamate bond-based polyurethane (OC-PU) and its application to fully self-healing integrated sensor arrays, regardless of the damaged direction. Synthesized OC-PU showed highly stretchable, hydrophobic, highly chemically resistant, and thermo-selectively self-healable properties, with elaborately optimizing soft segments of PDMS and trifunctional crosslinker diethylenetriamine. OC-PU exhibited superior mechanical properties with elongation at break of 1076 %, Young's modulus of 1.2 MPa, and an excellent self-healing efficiency of 93.7 % when heated at 65 ℃. Based on novel OC-PU, a self-healing capacitive pressure sensor assembling OC-PU/galinstan/Ni composite electrodes and OC-PU dielectric film through self-healing process. The fabricated sensor could detect body motions with stable operation in water, and also could recover sensitivity after repetitive self-healing from a complete bisection. Furthermore, a fully self-healing stretchable array of pressure sensors with layered structure is fabricated via photolithography using galinstan interconnections selective wet onto patterned Au grid lines. This work suggests a high potential application of our self-healing polyurethane with novel functionality to developing fully self-healing integrated wearable devices.