Photopolymer functionalization with trace amounts of bimetallic AgTi nanoparticles for antibacterial vat photopolymerization-produced parts

Abstract Functionalization of additive manufacturing (AM) polymer feedstocks by incorporating nanoparticles (NPs) has gained considerable attention to produce functional polymer parts with tailored physicochemical properties, addressing the demand for customizable parts with unprecedented geometric freedom. In particular, vat photopolymerization (VPP) holds great potential for fabricating intricate, miniaturized, and functionalized items at superior spatial resolution. However, large fractions of nanoadditives commonly employed are prone to agglomerating and affect the processability. Herein, a facile composite formulation approach is introduced to obtain photopolymers functionalized with very low amounts of silver-titanium (AgTi) NPs and Ag-decorated titanium dioxide (TiO 2 ) NPs. Colloidal NPs of only 5.8 nm mean size are synthesized via pulsed laser ablation in liquids (PLAL), and subsequently incorporated into the polymer matrix via direct-mixing. Working curves reveal that the NPs reduce the critical energies required for VPP, confirming that the processability is maintained, which is attributed to the low NP amounts of only ≤0.05 wt% used in this study. While the mechanical properties remain unaffected by the NP incorporation, the composites exhibit antibacterial activity, as manifested by effectively inhibiting Gram-positive/-negative bacteria attachment even at only 0.05 wt% NP loading. The versatility and simplicity of the functionalization approach render it attractive for using arbitrary colloidal NP systems, extending the diversity of functionalities added to photopolymers at a minimal NP employment.