Immobilization of TiO2 nanoparticles on polymeric substrates by using electrostatic interaction in the aqueous phase

A new method for immobilization of TiO2 nanoparticles on polymeric substrates was developed to facilitate photocatalytic purification of contaminated air and water. TiO2 was immobilized by dipping a polymeric substrate, treated with polyvinyl chloride–polyvinyl acetate (PVC–PVA) copolymer and/or SiO2, into a TiO2/water suspension. The surface zeta potential measurement on TiO2 and treated polymers implies that this method is based on an electrostatic interaction between positively charged TiO2 and the negatively charged treated surface of the polymeric substrate. This method precludes the enwrapping of TiO2 particles in binding components, which has been a drawback of conventional methods, and enables bonding of the TiO2 nanoparticles on the substrate surface at high density. The TiO2-immobilized nonwoven polyester (PES) prepared using this method exhibited high photocatalytic activity for decomposing the air contaminant toluene. Furthermore, this method was applicable to polypropylene (PP) nonwoven, polyethylene (PE) nets and PE and PP films. TiO2 bonding was inhibited on PP by treatment with PVC–PVA copolymer and better TiO2 immobilization was observed on SiO2-treated PP.