Self-cleaning performance evaluation of commercial photocatalyst coating materials trough 5 years outdoor exposure

Author(s): Kenji Motohashi, Tatsuo Inukai
Paper category : conference
Book title: International RILEM Symposium on Photocatalysis, Environment and Construction Materials - TDP 2007
Editor(s): P. Baglioni and L. Casssar
Print-ISBN: 978-2-35158-056-1
e-ISBN: 978-2-35158-057-8
Publisher: RILEM Publications SARL
Publication year: 2007
Pages: 307 - 313
Total Pages: 7
Language: English

Abstract: Self-cleaning performance of various commercial photocatalyst coatings was evaluated through five years outdoor exposure. Optical measurement was carried out for evaluation of self-cleaning performance. At the same time, chalking degrees were measured for evaluation of surface degradation. Scanning electron micrograph observation was also performed for some specimens. Photocatalysis activity of the coating materials were evaluated through measurement of wet methylene blue decomposition and water contact angles.
According to the previous paper [1], self-cleaning effects of the commercial photocatalyst coating products had distinctly demonstrated in comparison with the ordinary coating products without photocatalyst application after 1 year outdoor exposure. After 5.5 years exposure, however, some coating materials showed little soiling and the other coating materials showed remarkable soiling phenomena.
A few coating products with little soiling showed remarkable chalking, which suggests surface degradation of the coating products. Moreover, rather many coating materials were found to possess no photocatalysis capability by measurement of wet methylene blue decomposition and water contact angles. It suggests that photocatalyst on the coating products had been lost during the outdoor exposure test.
In conclusion, it is important to evaluate stability of photocatalyst layers or photocatalyst on the surface of coating materials. And it is important to evaluate durability of coating binders against photocatalysis in order to prevent from photocatalyst disappearance and from remarkable chalking.

Online publication: 2011-07-01
Publication type : full_text
Public price (Euros): 0.00