Effect of external fields applied during hot-water treatment on the aspect ratio of nanocrystallites formed on SiO2·TiO2 coatings derived from sol–gel techniques

• Published in: Journal of sol-gel science and technology 2010-12, Vol.56 (3), p.345-352
• Main Authors: Prastomo, Niki, Kimata, Kouji, Daiko, Yusuke, Muto, Hiroyuki, Kogure, Toshihiro, Sakai, Mototsugu, Matsuda, Atsunori
• Format: Article
• Language: English
• Subjects: Aspect ratio; Ceramics; Chemical precipitation; Chemistry; Chemistry and Materials Science; Coatings; Colloidal gels. Colloidal sols; Colloidal state and disperse state; Composites; Concentration gradient; Electric charge; Exact sciences and technology; General and physical chemistry; Glass; Inorganic Chemistry; Materials Science; Nanocrystals; Nanotechnology; Natural Materials; Optical and Electronic Materials; Original Paper; Precipitates; Silicon dioxide; Sol-gel processes; Titanium dioxide; Vibration; Water treatment
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-010-2312-8

SiO 2 ·TiO 2 coatings were prepared by a sol–gel route. The effect of the external fields including mechanical vibration and electric charge applied during hot-water treatment on titania precipitation at the surface of the coatings was investigated. The shape of the resulting precipitates tended to elongate by applying vibration in a parallel or perpendicular direction, or by applying an electric charge. The organization of titania nanocrystallites possibly occurs because of the concentration gradient of dissolved titania species generated by the external fields during the hot-water treatment. A maximum aspect ratio of 38.1 was achieved for the precipitate prepared by hot-water treatment performed under parallel vibration for 5 h. The shape of the resulting precipitates was also influenced by the content of TiO 2 in the SiO 2 ·TiO 2 coating, with a smaller proportion of TiO 2 increasing the aspect ratio of the resulting precipitate.