Facile Synthesis of Thermo-responsive TiO₂/PNIPAM Composite with Switchable Photocatalytic Performance

In this paper, a facile and efficient method was performed to prepare the thermo-responsive Poly(N-isopropylacrylamide)/TiO₂ (TiO₂/PNIPAM) with the dispersing of TiO₂ nanoparticles into PNIPAM. The structures of nanoparticles and the grafted polymer were confirmed by X-ray diffraction (XRD), Raman spectra, Fourier transform infrared spectra (FT-IR) and Dynamic Light Scattering (DLS). The interactions between the two components were studied by X-ray photoelectron spectroscopy (XPS), and the morphology of TiO₂/PNIPAM was observed by scanning electron microscopy (SEM). The results showed that TiO₂ exhibited homogeneous dispersion, without sacrificing the properties of TiO₂. Furthermore, The composite was used to photocatalytic degradation of Methylene blue (MB). The highest MB removal efficiency is 86.3 %. The photocatalytic activities above or below the lower critical solution temperature (LCST) of PNIPAM was also investigated. The experiment results show that the existence of PNIPAM contributed not only the thermo-responsive abilities to TiO₂, but also the enhanced photocatalytic activities to TiO₂. In addition, the corresponding mechanism of enhanced photocatalytic activity was proposed. The results manifest that the well-designed TiO₂/PNIPAM is a promising candidate in wastewater treatment application.