We study the structure and orientation of water molecules at water/alkane and water/polydimethylsiloxane interfaces with surface specific intensity and heterodyne-detected vibrational sum-frequency generation (HD-VSFG) spectroscopy. We observe that the hydrogen-bond structure of the water molecules is enhanced at these interfaces compared to the water/air interface. We also find that the water molecules at the interface show a net orientation of their O–H groups pointing towards to the hydrophobic layer.

Y.L.A. Rezus (Yves)
J. Chem. Phys.
Ultrafast Spectroscopy

Strazdaite, S., Versluis, J., & Bakker, H. (2015). Water orientation at hydrophobic interfaces. J. Chem. Phys., 143(Article number: 084708), 1–6. doi:10.1063/1.4929905