PLLA/(MWCNTs-ZnO)@PDA composite with NIR-light induced shape memory effect, antibacterial properties and 3D printability

PLLA based shape-memory polymer composites with multifunctions have attracted growing attention in biomedical applications. Generally, a single nanofiller has the problem of insufficient functionalization and easy aggregation. Therefore, we design and fabricate polydopamine (PDA) surface modified MWCNTs-ZnO hybrid nanostructure ((MWCNTs-ZnO)@PDA). The dispersion of (MWCNTs-ZnO)@PDA in PLLA is improved in comparison with the pristine MWCNTs or ZnO. The results indicate that the (MWCNTs-ZnO)@PDA nanosystem shows a synergistic effect on the mechanical properties and photothermal properties of the composites. Comparative analysis with neat PLLA demonstrates a remarkable 17% increase in tensile strength and a 19% increase in elongation at break for PLLA/(MWCNTs-ZnO)@PDA composite. Additionally, the composites exhibit excellent NIR light-induced shape memory effects with a shape recovery ratio reaching 100%. Moreover, PLLA/ (MWCNTs-ZnO)@PDA composites show favorable antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Furthermore, the polymer composites display good 3D printability, and the 3Dprinted porous scaffold possesses high compressive strength and modulus. Also, the PLLA/(MCNTs-ZnO)@PDA scaffold can be compressed into a compact size and recover its original shape under NIR light irradiation. This work provides an approach to prepare novel shape-memory polymer composites with multifunctions including high strength, light-induced shape-recovery, antibacterial properties and printability.