Lotus Effect Amplifies Light-Induced Contact Angle Switching

Autor:	Antonio A. Garcia, J. W. Dailey, J. L. Taraci, Rohit Rosario, T. Clement, Mark A. Hayes, Devens Gust, S. T. Picraux
Rok vydání:	2004
Předmět:	Spiropyran Materials science business.industry Nanowire Surfaces Coatings and Films Contact angle chemistry.chemical_compound Hysteresis Optics chemistry Wetting transition Monolayer Materials Chemistry Wetting Lotus effect Physical and Theoretical Chemistry Composite material business
Zdroj:	The Journal of Physical Chemistry B. 108:12640-12642
ISSN:	1520-5207 1520-6106
Popis:	A rough surface morphology is shown to significantly amplify the light-induced change in water contact angle of a photoresponsive surface. Smooth Si surfaces and fractally rough Si nanowire surfaces grown on a Si substrate were studied, both coated with a hydrophobic monolayer containing photochromic spiropyran molecules. Under visible irradiation the spiropyran is in a closed, hydrophobic form, whereas UV irradiation converts the spiropyran to a polar, hydrophilic form, reducing the contact angle. The superhydrophobic nanowire surface both amplifies the light-induced contact angle change by a factor of 2 relative to a smooth surface and reduces the contact angle hysteresis. As a result the UV-induced advancing contact angle is lower than the receding contact angle under visible irradiation, allowing water drops to be moved solely under the influence of a UV−visible light gradient. The amplification of the reversible light-induced wetting angle change was predicted using the Wenzel model for fractally rou...
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::85f08332499cb074562466ab967d71e5 https://doi.org/10.1021/jp0473568 Zobrazit plný text záznamu