Deposition of TiO₂ Nanoparticles on Porous Polylactic Acid Fibrous Substrates and Its Photocatalytic Capability.

Abstract

In this work, porous electrospun polylactic acid (PLA) fibers with high specific surface area and excellent biodegradability were examined as the support of titanium dioxide (TiO2) nanoparticles (NPs). The deposition of TiO2 NPs on porous electrospun PLA fibrous substrates was accomplished through the hydrolysis of titanium tetra isopropoxide (TTIP) under ultrasonic irradiation, and the effects of the TTIP concentrations on structure and property of composite fibers was also investigated. The prepared TiO2-deposited PLA composite fibers were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), High-resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller (BET) and thermogravimetric analyzer (TGA). The results indicated that the anatase TiO2 NPs with an average size of about several tens of nanometers to 200 nm were successfully loaded onto surface of porous PLA fibrous substrates. Meanwhile, the TiO2 NPs liked a "double-edged sword," overfull deposition of TiO2 NPs had negative effect on the properties of composite fibers. Under the optimized condition, the TiO2 NPs deposited dispersedly on the surface of PLA fibers without severe agglomeration and this structure performed with a high specific surface area of 64.8 m2/g, which was 5 times as large as pure PLA nanofibers (12.9 m2/g). In addition, the prepared TiO2-loaded composite fibers showed satisfactory removal efficiency on MB, the MB concentration decreased about 75%, which was remarkably higher than that of pure PLA fibers. Compared with powdery TiO2, TiO2-loaded composite fibers showed considerable photocatalytic activity, as well as easier operation, confirming this hybrid composite fibers was suitable for the easier operated application of TiO2.