What x rays can tell us about the interfacial profile of water near hydrophobic surfaces

Ahmet Uysal, Miaoqi Chu, Benjamin Stripe, Amod Timalsina, Sudeshna Chattopadhyay, Christian M. Schlepütz, Tobin J Marks, Pulak Dutta

Research output: Contribution to journalArticle

36 Citations (Scopus)

Abstract

The free surface of water and the interface between water and a hydrophobic surface both have positive interface energies. The water density near a free surface drops below the bulk density, and thus it is expected that water near a hydrophobic surface will also show a density depletion. However, efforts by multiple groups to detect and characterize the predicted gap at water-hydrophobic interfaces have produced contradictory results. We have studied the interface between water and fluoroalkylsilane self-assembled monolayers using specular x-ray reflectivity and analyzed the parameter-space landscapes of the merit functions being minimized by data fitting. This analysis yields a better understanding of confidence intervals than the customary process of reporting a unique best fit. We conclude that there are unambiguous gaps at water-hydrophobic interfaces when the hydrophobic monolayer is more densely packed.

Original languageEnglish
Article number035431
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume88
Issue number3
DOIs
Publication statusPublished - Jul 17 2013

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X rays
Water
profiles
water
x rays
Self assembled monolayers
confidence
Monolayers
depletion
intervals
reflectance
energy

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

Cite this

Uysal, A., Chu, M., Stripe, B., Timalsina, A., Chattopadhyay, S., Schlepütz, C. M., ... Dutta, P. (2013). What x rays can tell us about the interfacial profile of water near hydrophobic surfaces. Physical Review B - Condensed Matter and Materials Physics, 88(3), [035431]. https://doi.org/10.1103/PhysRevB.88.035431

What x rays can tell us about the interfacial profile of water near hydrophobic surfaces. / Uysal, Ahmet; Chu, Miaoqi; Stripe, Benjamin; Timalsina, Amod; Chattopadhyay, Sudeshna; Schlepütz, Christian M.; Marks, Tobin J; Dutta, Pulak.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 88, No. 3, 035431, 17.07.2013.

Research output: Contribution to journalArticle

Uysal, Ahmet ; Chu, Miaoqi ; Stripe, Benjamin ; Timalsina, Amod ; Chattopadhyay, Sudeshna ; Schlepütz, Christian M. ; Marks, Tobin J ; Dutta, Pulak. / What x rays can tell us about the interfacial profile of water near hydrophobic surfaces. In: Physical Review B - Condensed Matter and Materials Physics. 2013 ; Vol. 88, No. 3.
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