Self Assembly of Honeycomb TiO<sub>2</sub> Coatings by Tea-Leaf Extracts as the Dispersoids

Abstract

Photo catalytic TiO 2 coatings with well defined honeycomb structure were successfully self-assembled on glass substrates by a simple "dip and burn sol-gel method". The crux of this new method is that the starting material for the sol-gel coating (the water solution of ammonium titanium citrate) was "doped" with "tea-leaf extracts". Tea-leaf extracts were completely dissolved in the water solution of ammonium titanium citrate and nucleate uniformly during the drying procedure of the coating precursor formation. This uniformly dispersed nucleation of the "tea-leaf extracts (tannin, catechin, etc.)" were extracted during calcinations and leaving honeycomb-cell like nano-structure in the TiO 2 coatings. Self-assembled cells were uniformly distributed in the TiO 2 coatings and the diameter of the cells was in the range of 200 -1000 nm. Fine honeycomb structures were clearly observed with microscopic observations.