Superhydrophilicity

Under light irradiation, water dropped onto titanium dioxide forms no contact angle (almost 0 degrees). This effect, called superhydrophilicity, was discovered in 1995 by the Research Institute of Toto Ltd. for titanium dioxide irradiated by sun light. [http://www.nanonet.go.jp/english/mailmag/2005/044a.html "Discovery and applications of photocatalysis —Creating a comfortable future by making use of light energy"] ]

Superhydrophilic material has various advantages. For example, it can defog glass, and it can also enable oil spots to be swept away easily with water. Such materials are already commercialized as door mirrors for cars, coatings for buildings, self-cleaning glass, etc. And another is the property of self-cleaning by the photodecomposition of dirt such as organic compounds adsorbed on the surface.

References

*“Layer-by-Layer Assembly of TiO2 Nanoparticles for Stable Hydrophilic Biocompatible Coatings” Dinesh S. Kommireddy, Dr. Amish Patel, Tatsiana G. Shutava, David K. Mills, Yuri M. Lvov. Journal of Nanoscience and Nanotechnology, 2005, 5, 1081-1087.