Toward Flexible Printed Electronics: A Spider-Silk-Inspired, Strong and Tough Thermoplastic Polyamide Elastomer

The advancement of intelligent and compliant flexible electronic devices demands polymer substrate materials that exhibit both high strength and toughness, which are critical for the performance and durability of printed circuits. Inspired by the structure of spider silk, we designed and synthesized a series of naphthalene-containing thermoplastic polyamide elastomers (TPAE) in this work. The optimized TPAE-N_40%-PEG_25% exhibits an impressive hydrogen bonding density of up to 41.8%, leading to outstanding mechanical properties: a tensile strength of 37.3 MPa, an elongation at break of 470.8%, and a remarkable toughness of 134.6 MJ/m³. When it was employed as a flexible substrate film (0.1 mm thickness), it reliably supported printed conductive traces, demonstrating stable electrical signal output under cyclic deformation. Furthermore, the substrate attached to fingers and wrists successfully monitored bending motions through consistent electrical responses, highlighting its potential for flexible strain sensors. Notably, the printed circuits can be completely removed by soaking in anhydrous ethanol for 12 h, enabling the full recovery and reuse of the substrate film. This spider-silk-inspired strategy provides a new design pathway for developing strong, tough, and sustainable polymer substrates for next-generation flexible electronics.