Dresden 2014 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 16: Interfaces and Thin Films II
CPP 16.10: Talk
Tuesday, April 1, 2014, 12:00–12:15, ZEU 114
Unexpected swelling characteristics of thermoresponsive polymer brush systems based on Poly(2-oxazoline)s — •Stefan Adam1,2, Klaus-Jochen Eichhorn1, Juan Carlos Rueda3, Manfred Stamm1,2, Mathias Schubert4, and Petra Uhlmann1 — 1Leibniz-Institut für Polymerforschung Dresden e.V., 01069 Dresden, Germany — 2Technische Universität Dresden, 01062 Dresden, Germany — 3Pontificia Universidad Católica del Perú, Lima, Peru — 4University of Nebraska-Lincoln, Lincoln, NE 68588, USA
Responsive polymer coatings or hydrogels are capable to change their structural and physical properties due to changes in the environmental condition (e.g. temperature). Poly(2-oxazoline)s (POX), being structural isomers to polyacrylamides (e.g. poly(N-isopropylacrylamide), PNiPAAm) can exhibit a lower critical solution temperature (LCST) in aqueous solution. Adjusting the molar mass or copolymerization with more hydrophilic/hydrophobic comonomers enables tuning the LCST towards higher/lower temperatures. A combinatorial Quartz Crystal Microbalance with Dissipation and Spectroscopic Ellipsometry setup was used to study quantitatively the swelling characteristics of POX brushes prepared by the "grafting to" method using pre-synthesized polymers with functionalized end groups. The swelling behavior of POX brushes was compared to the phase transition of a corresponding aqueous polymer solution, determined by turbidity measurements. While all POX solutions show sharp transition curves in aqueous solution, an unexpected continuous reversible swelling of grafted POX could be observed over a wide temperature range.