Preparation and characterization of porous titanium dioxide sulfonated polystyrene composite microspheres with amphiphilicity

Abstract

Porous particles with amphiphilicity were prepared by a nonpolymeric pore-formation process with the sulfonation of polystyrene microspheres. Nano titanium dioxide (TiO2) particles were then grafted onto the surface via a sol-gel method to finally form the composite particles. The effects of the mass ratio of ethanol (EtOH) to water, temperature, and solubility parameter on the pore-formation process is discussed in detail. The morphology, porous structure, and wetting properties of the particles were studied by scanning electron microscopy, transmission electron microscopy, Fourier transform infrared (FTIR) spectroscopy, and contact angle measurement. The results show that porous sulfonated polystyrene (SP) microspheres could be fabricated at 60°C with a 1: 1 mass ratio of EtOH-water and a solubility parameter of 29.69 MPa1/2. The TiO2 particles were determined to be grafted onto the SP microspheres by physical-bond interaction on the basis of FTIR analysis. The contact angles for both water (aqueous-phase) and various organic solvent (oil-phase) droplets with different polarities on the surface of compressed tablets of TiO2-SP powder were all lower than 30°; this indicated excellent amphiphilicity in the composite particles. Highlights: Amphiphilicity was achieved by sulphonation of polystyrene (PS) microspheres. Porous structure was formed by a non-polymeric pore-formation process. With sulfonic group, the polymer particles were easy to composite with inorganic particles. The porous structure and excellent amphiphilicity contributed to expanded applications. Copyright © 2013 Wiley Periodicals, Inc.