Multifunctional behaviour of PLA biomacromolecules by GNP/TiO ₂ hybrid nanofiller integration: Amplifying strength, solvent sorption resistance and antimicrobial properties

This study delves into the synergistic effect of bi-nanofillers, 0-D titanium dioxide (TiO 2 ), and 2-D graphene nanoparticles (GNP) on the microstructure, sorption, anti-microbial, static, and dynamic mechanical behaviour of polylactic acid (PLA). The tensile strength, critical stress intensity factor, and storage modulus (at the optimum filler content of 1wt% GNP and 0.5 wt% TiO 2 ) of P/1 G/0.5T sample at room temperature exhibited an increase of 52%, 42%, and 40% respectively with respect to PLA. This increment is accredited to the physical entanglement of dual nanofillers with PLA chains. The hybrid system revealed a higher surface roughness in atomic force microscopy (AFM) which accounts for the hydrophilic nature of contact angle measurements. The heterogeneous nucleation effect of dual nanofillers improved the percentage of crystallinity by 54% as obtained from differential scanning calorimetry (DSC). The X-ray diffraction (XRD) analysis showed the formation of large number of small crystals in the P/1G/0.5T sample. The amphiphilicity of the hybrid sample reduced the diameter of incubation halos with Staphylococcus aureus in the presence of biocide, ciprofloxacin as it creates a hostile environment for bacterial growth.