Dresden 2011 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 23: Poster: Semicrystalline Polymers, Polymer Crystallization and Self-Assembly

CPP 23.5: Poster

Dienstag, 15. März 2011, 18:00–20:00, P2

Conformational changes of oligo(ethlene glycol) under aqueous conditions during growth and at elevated temperature monitored with PMIRRAS — •Stefan Zorn, Alexander Gerlach, and Frank Schreiber — Institut für Angewandte Physik, Universität Tübingen, Tübingen, Germany

Oligo(ethylene glycol) SAMs are a model system for protein resistant SAMs and are subject of comprehensive research for a better understanding of protein resistance. Recent SFG and IR studies show a strong effect of water on the SAM structure and imply a connection of this interaction to the biofouling properties [1]. The exact mechanism, however, is still under discussion. In this study we were able to monitor the growth of hexa(ethylene glycol) SAMs in real-time under aqueous conditions (in-situ) with polarisation modulation infrared spectroscopy (PMIRRAS) using a home built thin liquid layer cell. Fitting of the absorption modes with Gaussians enabled us to determine their area, width and position. We observed a conformational reordering of the OEG moiety from all-trans / helical to predominantly helical and an enhancing crystallinity. In addition, we were able to study the SAM-water interaction in the different growth states. It is the higher the lower the surface coverage [2]. Further, we investigated hexa(ethylene glycol) SAMs at elevated temperatures under in-situ conditions. Our observations contribute to the understanding of biofouling properties and stability of OEG-SAMs and show the possibilities and importance of PMIRRAS in-situ investigations. [1] M.W.A. Skoda et al., Langmuir 23 (2007) 970; [2] S. Zorn et al., PCCP 12 (2010) 8985