Controlling Low-Temperature Growth of Titanium Dioxide Confined in Poly(<scp>d</scp>,<scp>l</scp>-Lactic Acid) Microparticles

Conventional materials for water remediation have limitations related to harsh chemicals and high energy costs; however, biopolymeric microparticles integrated with titania have shown promise due to their nontoxicity and photocatalytic capability. Herein, we investigated the growth of titanium dioxide (TiO2) within the confinements of a poly(d,l-lactic acid) (PLA) porous matrix under a lower temperature of 60 °C to obtain PLA/TiO2 nanocomposite microparticles. We tested the effects of titania alkoxide precursor chemistry, solvent chemistry and composition, and the ratio of PLA/titania on the efficiency of PLA–TiO2 integration to obtain photocatalytic PLA/TiO2 microsponges, and used the degradation of an organic dye, rhodamine 6G, in an aqueous solution upon UV irradiation in the presence of PLA/grown TiO2 nanocomposite microparticles as a probe of the microparticle photocatalytic efficiency. Thermogravimetry and size-exclusion chromatography analyzed the effect of in situ TiO2 growth within the PLA porous matrix on microparticle composition and thermal stability. Raman spectroscopy and X-ray diffraction revealed the presence of a mixed amorphous/crystalline (anatase-rutile) TiO2 nanophase in the grown PLA/TiO2 microsponges. In addition to developing approaches for water remediation, this study offers insights into the control of the interactions at the PLA/TiO2 interfaces, which is crucial to advancing sustainable synthesis strategies for developing polymeric nanocomposite microparticles.