Regensburg 2007 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 14: Biological Systems

CPP 14.6: Talk

Tuesday, March 27, 2007, 11:30–11:45, H47

Hydration of Oligo(ethylene glycol) Self-Assembled Monolayers: An in situ PMIRRAS study — •Maximilian Skoda^1,2, Robert Jacobs³, and Frank Schreiber² — ¹Physical and Theoretical Chemistry Laboratory, Oxford University, UK — ²Angewandte Physik, Universität Tübingen, Germany — ³Chemistry Research Laboratory, Oxford University, UK

The interaction with water of protein-resistant monolayers (SAMs), self-assembled from (triethylene glycol) terminated thiol HS(CH₂)₁₁(OCH₂CH₂)₃-OMe solutions, was studied using in and ex situ polarization-modulated Fourier transform infrared spectroscopy. In particular, shifts in the position of the characteristic C-O-C stretching vibration were observed after the monolayers had been exposed to water. The shift in frequency increased when the SAM was observed in direct contact with a thin layer of water. It was found that the magnitude of the shift also depended on the surface coverage of the SAM. These findings suggest a rather strong interaction of oligo(ethylene glycol) SAMs with water and indicate the penetration of water into the upper region of the monolayer. Since the complexity of this system requires careful consideration of experimental parameters, some theoretical aspects of the signal generation will be discussed.