Lotus effect amplifies light-induced contact angle switching

Rohit Rosario, John Devens Gust, Antonio A. Garcia, Mark Hayes, J. L. Taraci, T. Clement, J. W. Dailey, S. T. Picraux

Research output: Contribution to journalArticle

207 Citations (Scopus)

Abstract

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 rough surfaces. The model and amplification effects are expected to apply to other types of stimuli-induced contact angle changes such as that by heat or electrical potentials.

Original languageEnglish
Pages (from-to)12640-12642
Number of pages3
JournalJournal of Physical Chemistry B
Volume108
Issue number34
DOIs
Publication statusPublished - Aug 26 2004

Fingerprint

Contact angle
Irradiation
Nanowires
Amplification
irradiation
nanowires
Water
Surface morphology
Hysteresis
Wetting
Monolayers
stimuli
water
wetting
hysteresis
Molecules
heat
gradients
Substrates
spiropyran

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

Cite this

Rosario, R., Gust, J. D., Garcia, A. A., Hayes, M., Taraci, J. L., Clement, T., ... Picraux, S. T. (2004). Lotus effect amplifies light-induced contact angle switching. Journal of Physical Chemistry B, 108(34), 12640-12642. https://doi.org/10.1021/jp0473568

Lotus effect amplifies light-induced contact angle switching. / Rosario, Rohit; Gust, John Devens; Garcia, Antonio A.; Hayes, Mark; Taraci, J. L.; Clement, T.; Dailey, J. W.; Picraux, S. T.

In: Journal of Physical Chemistry B, Vol. 108, No. 34, 26.08.2004, p. 12640-12642.

Research output: Contribution to journalArticle

Rosario, R, Gust, JD, Garcia, AA, Hayes, M, Taraci, JL, Clement, T, Dailey, JW & Picraux, ST 2004, 'Lotus effect amplifies light-induced contact angle switching', Journal of Physical Chemistry B, vol. 108, no. 34, pp. 12640-12642. https://doi.org/10.1021/jp0473568
Rosario R, Gust JD, Garcia AA, Hayes M, Taraci JL, Clement T et al. Lotus effect amplifies light-induced contact angle switching. Journal of Physical Chemistry B. 2004 Aug 26;108(34):12640-12642. https://doi.org/10.1021/jp0473568
Rosario, Rohit ; Gust, John Devens ; Garcia, Antonio A. ; Hayes, Mark ; Taraci, J. L. ; Clement, T. ; Dailey, J. W. ; Picraux, S. T. / Lotus effect amplifies light-induced contact angle switching. In: Journal of Physical Chemistry B. 2004 ; Vol. 108, No. 34. pp. 12640-12642.
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