Fully Bio-Based, Tough, and Room-Temperature Shape Adaptive Poly(lactic acid) Blend for Green Electronics

The escalating global e-waste crisis and demand for sustainable electronics drive the urgent need for high-performance bio-based polymers. Poly(lactic acid) (PLA), a leading bio-based polyester, suffers from inherent brittleness and limited shape adaptability, hindering its application in green electronics. Herein, we report a fully bio-based, tough PLA blend with excellent room-temperature shape adaptability (RTSA) via melt blending with a low-molecular-weight bio-based polyester (l-BPE). Owing to poor compatibility and low molecular weight, the l-BPE disperses as multiscale domains, effectively toughening PLA via a multiple microcracking mechanism while preserving PLA's high glass transition temperature (T_g). The PLA/l-BPE20 achieves a toughness of 71.9 ± 5.6 MJ/m³, a tensile strength of 39.5 ± 1.1 MPa, and excellent RTSA with high shape fixation rates (>99% in tensile mode, >82% in bending mode). The RTSA stems from the synergistic effect of high T_g-restricted chain mobility, oriented chains at microcracks, and low l-BPE resilience. As a wire protective layer, the blend maintains circuit functionality in complex deformed shapes (spiral, W-shape) without cracking or entropy-driven recovery, outperforming rigid PLA and flexible PBAT-based layers. This work provides a facile incompatible-blending strategy to tough PLA and endow RTSA, enabling high-performance bio-based materials for green electronics.