Berlin 2015 – scientific programme

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DS: Fachverband Dünne Schichten

DS 20: Focussed Session: In-situ optical spectroscopy

DS 20.4: Invited Talk

Wednesday, March 18, 2015, 11:00–11:30, H 0111

Correlation of IR spectra with thin film structure at solid-water interfaces — •Karsten Hinrichs — Leibniz-Institut für Analytische Wissenschaften - ISAS - e.V., 12489 Berlin, Germany

A crucial point for infrared characterizations at solid/liquid interfaces in electrochemistry, polymer science and biosensing is the understanding of spectra-structure correlations. Optical layer calculations are required for quantitative conclusions on the structure from measured infrared spectra, in particular in the range of water vibrational bands. For infrared measurements of thin films in a flow cell spectroscopic ellipsometry was adapted. Exemplarily the stimuli-responsive properties of polymer brushes will be discussed, e. g. swelling degree, water content, and molecular interactions and dissociation of functional groups within an ultrathin polymer layer as well as the pH- and temperature-responsive adsorption and desorption of proteins. Current work is related to reduce the needed volume of liquids by use of microfluidic cells, to increase the lateral resolution by infrared microscopy, to enhance the detection limit by nano/microstructured substrates and to complement the optical layer simulations by optical calculations (e.g. using rigorous coupled-wave analysis (RCWA), finite-difference time-domain method (FDTD)).