Photocatalytic and antifouling properties of electrospun TiO₂ polyacrylonitrile composite nanofibers under visible light

Polyacrylonitrile and its TiO₂ composites were electrospun into nanofibers in N, N’-dimethylformamide for photocatalysis and antifouling experiments. The resultants nanofibers were characterized using field emission scanning microscope, Fourier transform infrared spectroscopy, x-ray diffraction, x-ray photoelectron spectroscopy and contact angle analyses. Fourier transform infrared spectroscopy confirmed the formation of polyacrylonitrile-TiO₂ composite nanofibers with their diameter ranging from 10 to 340 nm. The x-ray photoelectron spectroscopy results indicate the formation of O–Ti–C bonds on polyacrylonitrile-TiO₂ matrix. polyacrylonitrile-TiO₂ and polyacrylonitrile nanofiber surfaces showed superhydrophobicity with water contact angle of 155 ± 1 and 154 ± 1, respectively at 120 s. The photocatalytic properties of polyacrylonitrile nanofibers and polyacrylonitrile-TiO₂ nanofibers were investigated under a simulated visible light source of 1000 W/m² using methylene blue. About 90% of methylene blue was degraded within 3 h of exposure using polyacrylonitrile-TiO₂ nanofibers while 55% methylene blue degradation was achieved for polyacrylonitrile nanofibers. Photoluminescence experiment conducted on both materials showed that polyacrylonitrile-TiO₂ could produce OH radicals 10-fold compared to polyacrylonitrile nanofibers. Antimicrobial tests were conducted using E. coli and Bacillus sp. The results showed that only polyacrylonitrile-TiO₂ under visible light hindered the growth of these bacteria with a greater effect on the Gram-positive bacterium, Bacillus sp. The photo-degradation and microbial growth inhibition properties of polyacrylonitrile-TiO₂ showed that the material could be used as an antifouling material under visible light.