Berlin 2015 – scientific programme
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DS: Fachverband Dünne Schichten
DS 20: Focussed Session: In-situ optical spectroscopy
DS 20.7: Talk
Wednesday, March 18, 2015, 12:15–12:30, H 0111
in-situ-ATR-FTIR characterization of thin films deposited from dopamine solutions — •Martin Müller1,2 and Birgit Urban1 — 1Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, — 2Technische Universität Dresden,01062 Dresden, Germany
in-situ-ATR-FTIR data on reactive deposition of catecholamines like dopamine (DA) at model surfaces aiming at structure and deposition mechanism of such bioinspired melanin like films are presented. The process initially observed by Lee is related to mussel adhesion via L-DOPA rich proteins and caused by a sequence of reaction steps suggesting transformation of DA into indole like moieties followed by polymerization to PDA. An ATR-FTIR pseudo-double-beam device and a thermostatable homebuilt flow cell were used. Germanium (Ge) internal reflection elements (IRE) were contacted with DA solutions allowing presence or absence of oxygen to certain degree. DA deposition was followed in dependence of either time or concentration. Via significant increases of characteristic IR bands from phenolic and aromatic species the formation of thin PDA films (SFM: 50 nm) at Ge could be followed in-situ. These bands revealed similar thermodynamic and kinetic adsorption behavior with rate constants of k=0.013 min-1. The comparison of ATR-FTIR and transmission-FTIR data on PDA films, on the blackish PDA phase above and on original melanin suggested, that surface and bulk phase initiated PDA material is different. Furthermore, application oriented studies revealed sustained release of model drugs and low protein adsorption at PDA films.