Metachromatic effects and photodegradation of basic blue on nanocrystalline titania films.
Titania nanocrystalline films have been deposited on solid substrates by a sol-gel procedure carried out in Triton X-100 reverse micelles. When the dye Basic Blue is adsorbed on these films, it demonstrates a strong metachromatic effect; that is, it aggregates, resulting in a blue shift of its absorption spectrum. Metachromasy in this system is related to the hydrophilicity of the film surface and to the humidity of the film environment. Films composed of 67% titania and 33% silica gave an intense and reversible metachromatic effect that can be exploited to make a handy humidity sensor. Photodegradation of Basic Blue on titania films is faster in humid environments than in dry environments, and this goes in parallel with metachromatic effects.
University of Patras, Engineering Science Department, 26500 Patras, Greece.
Elias
E
Stathatos
Panagiotis
P
Lianos
Christos
C
Tsakiroglou
D000327:Adsorption; D004396:Coloring Agents / Q000737:chemistry / Q000528:radiation effects; D003460:Crystallization; D008567:Membranes, Artificial; D008823:Micelles; D049329:Nanostructures / Q000737:chemistry*; D010777:Photochemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry*; D017155:Wettability
D004396:Coloring Agents; D008567:Membranes, Artificial; D008823:Micelles; C009495:titanium dioxide; D012822:Silicon Dioxide; D014025:Titanium