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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 10: Poster: Structure and Dynamics of Responsive Hydrogels
CPP 10.4: Poster
Montag, 22. März 2010, 16:30–18:00, Poster C
Collapse behavior of thermo-responsive poly(2-oxazoline) copolymers — •Christine M. Papadakis1, Stephan Salzinger2, Stephan Huber2, Joseph Adelsberger1, Anastasia Golosova1, Andreas Meier-Koll1, Peter Busch3, Sandor Balog4, and Rainer Jordan2 — 1TU München, Physikdepartment E13, Garching — 2TU München, Department Chemie, Garching — 3JCNS, FRM II, Garching — 4PSI, Villigen, Switzerland
The poly(2-oxazoline) (POx) system offers the possibility to tune the water-solubility in a wide range. Moreover, using 2-isopropyl (iPr) as a side group results in a thermo-responsive polymer with a lower critical solution temperature (LCST) [1].
We have investigated the LCST behavior of an iPrOx homopolymers as well as a gradient copolymer with few n-nonyl-2-oxazoline (NOx) groups in aqueous solution. The LCST and the molecular aggregation behavior were studied using single molecule as well as ensemble characterization techniques (fluorescence correlation spectroscopy (FCS), turbidimetry and small-angle neutron scattering). We have found that iPrOx in aqueous solution shows mean-field temperature behavior and forms large aggregates above the LCST. In contrast, the collapse behavior of the gradient copolymer shows more complex behaviour. In addition to the large aggregates formed at the LCST, the polymers form small globules which gradually grow as temperature is increased.
[1] R. Jordan, C. M. Papadakis, et al., Colloid Polym. Sci. 282, 833 (2004); Macromol. Chem. Phys. 208, 1402 (2007); Colloid Polym. Sci. 285, 491 (2007); Macromol. Chem. Phys. 209, 2248, (2008).