Fabrication and characterization of titania inverse opals using supercritical carbon dioxide

초록

Titania inverse opals (TIO) with macropores were synthesized via hydrolysis of titanium tetra-isopropoxide (TTIP) in supercritical carbon dioxide (scCO(2)). Colloidal polystyrene (PS) particles packed in a regular arrangement were used as a template. A mixture of scCO(2), TTIP along with ethanol (EtOH) and distilled water was used as an impregnation medium to the voids of PS template. After the sol-gel coating reaction of the titania precursor in the voids and a subsequent thermal treatment, an inverted titania opal structure with high periodicity was obtained. The TIO was characterized by field emission scanning electron microscopy (FE-SEM). Raman spectroscopy and X-ray diffractometry (XRD). From the results of analysis, we conclude that the TIO synthesized in this study have anatase crystalline structure and have mean pore size diameter of 670-700 nm. The change in particle sizes is equivalent to only 2-5% shrinkage from the original PS latex spheres (715 nm). This represents much improved result compared to the products made by other methods where 20-30% shrinkage is common. (C) 2012 Elsevier EN. All rights reserved.

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