Research on self-healing photocurable 3D-printed conductive polycaprolactone-based composites.

The overexploitation of fossil resources and increasing environmental concerns have made the development of sustainable material systems an imperative. Although vat photopolymerization 3D printing allows precise shaping and minimizes material waste, it is often limited by the non-degradability and lack of functionality of conventional photosensitive resins. To overcome these constraints, this study reports a novel photopolymerization system that integrates biodegradability, self-healing, and electrical conductivity through molecular design and functional composites based on biodegradable polycaprolactone (PCL). A 4B-PCL was first synthesized via microwave-assisted polymerization and subsequently end-functionalized to yield a vinyl-modified macromer (4B-PCL-IEM). This resin exhibited outstanding performance in an optimized photopolymerization formulation, achieving a gel content exceeding 90%, a swelling rate below 5%, a 35% increase in tensile strength while maintaining over 200% elongation at break, shape memory recovery greater than 95%, and suitability for high-precision 3D printing. Furthermore, multifunctional composite resins were constructed by incorporating polyether thiourea (TUEG-IEM), magnetic particles (Fe3O4-3 TPM), and graphene. With 6 wt% graphene content, the composite achieved an electrical conductivity of 0.17 S/m, a self-healing efficiency of 81% within 4 h, along with significantly improved hydrophilicity and degradability. Finally, using optimized printing parameters, we successfully fabricated functional conductive circuits and devices, thereby providing a promising material platform for sustainable flexible electronics.