A bio-based thermoplastic polyurethane with triple self-healing action for wearable technology and smart textiles

Self-healing bio-based polymers are an emerging class of materials with promise in both limiting the use of non-renewable monomers in polymer production and increasing the life span of materials through the healing of damage that would otherwise cause the material to fail. This study reports a novel biobased thermoplastic polyurethane (TPU) with triple self-healing action, showing excellent stretchability and self-healing behaviour. The effect of hard segment percentage on the mechanical, thermal, and hydroscopic properties was investigated. The optimised TPU exhibits an elongation at break of 1871%, an ultimate tensile strength (UTS) of 0.36 MPa and a Shore A hardness of 40. The self-healing efficiencies for elongation at break and UTS reach above 90% after only three hours under ambient conditions due to triple action. The TPU shows skin-mimicking mechanical properties, and hydrophobicity, and acts as a stretchable, self-healing substrate for printing conductive circuits, making it a promising candidate for use in stretchable conductors, wearable devices and electronic skin. This bio-based self-healing polymer also shows high processibility into uniformly sized fibres, allowing use in smart elastic textiles.