Granick Research Group
University of Illinois at Urbana-Champaign
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Synchrotron x-ray reflectivity measurements of the interface between water and methyl-terminated octadecylsilane monolayers with stable contact angle >100 degree conclusively show a depletion layer, whether or not the water is degassed. The thickness is of order one water molecule: 2–4 A° with electron density <40% that of bulk water. Considerations of coherent and incoherent averaging of lateral inhomogeneities show that the data cannot be explained by "nanobubbles." When the contact angle is lower, unstable in time, or when monolayers fail to be sufficiently smooth over the footprint of the x-ray beam, there is no recognizable depletion.


  1. Steve Granick and Sung Chul Bae, "A Curious Antipathy for Water" (Perspective), Science 322, 1477 (2008). [PDF]
  2. A. Poynor, L. Hong, I. K. Robinson, S. Granick, Z. Zhang, P. A. Fenter, "How Water Meets a Hydrophobic Surface", Phys. Rev. Lett. 97, 266101 (2006) [PDF]. Highlighted: Nature 445, 129 (2007). [PDF]. [In the news]. Highlighted: Nature 445, 831 (2007). [PDF]
  3. X. Zhang, Y. Zhu, and S. Granick, "Hydrophobicity at a Janus Interface," Science 295, 663 (2002). [PDF] [In the news]
  4. Y. Zhu and S. Granick, "Viscosity of Interfacial Water," Phys. Rev. Lett. 87, 096104 (2001). [PDF]. Highlighted: Nature News (2001). [PDF]

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The Granick research group is an affiliated member of the Materials Research Laboratory,
the Beckman Institute, the Center for Nanoscale Science and Technology.