Preparation and Characterization of Raspberry-like SiO2 Particles by the Sol-gel Method Regular Paper

Raspberry-like SiO2 particles with a nano-micro-binary structure were prepared by a simple sol-gel method using tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) as precursors. The chemical components and morphology of the SiO2 particles were characterized by Fourier transform infrared spectroscopy (FT-IR) and a Transmission electron microscope (TEM). The surface topography and wetting behaviour of the raspberry-like SiO2 surface were observed with a Scanning electron microscope (SEM) and studied by the water/oil contact angle (CA), respectively. The thermal stability of the prepared SiO2 particles was characterized by TGA analysis. The results show that the highly dispersed SiO2 particles initially prepared by the sol-gel method turn into raspberry-like particles with during the aging process. The raspberry-like SiO2 particles show superhydrophobicity and superoleophilicity across a wide range of pH values. The SiO2 particles were thermally stable up to 475 degrees C, while above this temperature the hydrophobicity decreases and finally becomes superhydrophobic when the temperature reaches 600 degrees C. The raspberry-like SiO2 particles which were prepared have potential applications in the fields of superhydrophobic surfaces, water-oil separation, anti-corrosion and fluid transportation.