Smart biodegradable PLA nanocomposites reinforced with ZnO and GO for thermomechanical and shape memory applications

The development of biodegradable smart materials with tunable thermomechanical and functional properties is essential for sustainable technologies in biomedical engineering, soft robotics, and responsive packaging. This work reports the fabrication and characterization of shape memory nanocomposites based on polylactic acid (PLA) reinforced with zinc oxide (ZnO) nanoparticles and graphene oxide (GO). While ZnO and GO have individually improved PLA performance, their synergistic incorporation has not been previously explored. Hybrid PLA–ZnO–GO composites were prepared via melt blending and analyzed using dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), nanoindentation, and thermomechanical cycling. Results demonstrated significant improvements in stiffness and thermal stability, with PLA–ZnO–6%GO exhibiting the highest storage modulus (~ 3.7 GPa) and enhanced degradation resistance. Nanoindentation revealed a modest rise in elastic modulus but decreased hardness and increased creep at higher GO loadings, highlighting dispersion challenges. Shape memory testing confirmed superior fixity and recovery, with PLA–ZnO–6%GO achieving nearly 100% fixity and ~ 98% recovery, reflecting the complementary reinforcement of ZnO and GO. These findings establish clear structure–property relationships and underscore the potential of hybrid nanofillers in designing multifunctional, biodegradable polymers with optimized thermomechanical and shape memory performance for next-generation smart material applications.