title: How water meets a very hydrophobic surface.
abstract: Is there a low-density region ("gap") between water and a hydrophobic surface? Previous x-ray and neutron reflectivity results have been inconsistent because the effect (if any) is subresolution for the surfaces studied. We have used x-ray reflectivity to probe the interface between water and more hydrophobic smooth surfaces. The depleted region width increases with contact angle and becomes larger than the resolution, allowing definitive measurements. Large fluctuations are predicted at this interface; however, we find that their contribution to the interface roughness is too small to measure.
authors.affiliation: Department of Physics & Astronomy, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Sudeshna
authors.initials: S
authors.lastname: Chattopadhyay
authors.forename: Ahmet
authors.initials: A
authors.lastname: Uysal
authors.forename: Benjamin
authors.initials: B
authors.lastname: Stripe
authors.forename: Young-Geun
authors.initials: YG
authors.lastname: Ha
authors.forename: Tobin J
authors.initials: TJ
authors.lastname: Marks
authors.forename: Evguenia A
authors.initials: EA
authors.lastname: Karapetrova
authors.forename: Pulak
authors.initials: P
authors.lastname: Dutta