Anti-bacterial activity of tetragonal and cross-pillar-shaped polyester/TiO2 filaments with photo-deposited silver and platinum nanoparticles

In this work, we tried to enhance anti-bacterial activity of fabric fibers by controlling the shape of filaments, such as tetragonal and cross-pillar, which led to an increase of the surface portion of filaments. With this purpose, silver and platinum nanoparticles were immobilized on the surface of TiO₂ nanoparticles within tetragonal and cross-pillar-shaped polyester (PET) filaments. The process consists of preparing 4 wt.% of TiO₂ compounding PET chips, melt-spinning of them and photo catalytic deposition of nanoparticles in sequence. To obtain tetragonal and cross-pillar-shaped morphologies of filaments, two different nozzles were used in the melt-spinning process. For the photo-deposition of metal nanoparticles, adsorption of the metal ions on the surface of the filaments was performed by immersing them in AgNO₃ and H₂PtCl₆ aqueous solutions, respectively, with simultaneous addition of methanol as a sacrificial agent. Photo-deposition was then carried out under ultraviolet light with an irradiation time of 300 s. The structural and antimicrobial properties of the tetragonal and cross-pillar-shaped PET/TiO₂ filaments with noble metal loaded were systematically characterized. Ag and Pt metal photo-deposited filaments showed excellent antimicrobial effect against the two types of bacteria, Staphylococcus aureus and Klebsiella pneumonia, under the dark condition.