Aqueous solution behavior of comb‐shaped poly(2‐ethyl‐2‐oxazoline) |
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Authors: | Christine Weber Sarah Rogers Antje Vollrath Stephanie Hoeppener Tobias Rudolph Nicole Fritz Richard Hoogenboom Ulrich S Schubert |
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Institution: | 1. Laboratory of Organic and Macromolecular Chemistry (IOMC), Friedrich‐Schiller‐University Jena, Humboldtstrasse 10, 07743 Jena, Germany;2. Jena Center for Soft Matter (JCSM), Friedrich‐Schiller‐University Jena, Philosophenweg 7, 07743 Jena, Germany;3. Dutch Polymer Institute (DPI), John F. Kennedylaan 2, 5612 AB Eindhoven, The Netherlands;4. ISIS‐STFC Neutron Scattering Facility, Harwell Science and Innovation Campus, Didcot, Oxon OX11 0QX, United Kingdom;5. Supramolecular Chemistry Group, Department of Organic Chemistry, Ghent University, Krijgslaan 281 S4, 9000 Ghent, Belgium |
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Abstract: | A series of comb polymers consisting of a methacrylate backbone and poly(2‐ethyl‐2‐oxazoline) (PEtOx) side chains was synthesized by a combination of cationic ring‐opening polymerization and reversible addition–fragmentation chain transfer polymerization. Small‐angle neutron scattering (SANS) studies revealed a transition from an ellipsoidal to a cylindrical conformation in D2O around a backbone degree of polymerization of 30. Comb‐shaped PEtOx has lowered Tg values but a similar elution behavior in liquid chromatography under critical conditions in comparison to its linear analog was observed. The lower critical solution temperature behavior of the polymers was investigated by turbidimetry, dynamic light scattering, transmission electron microscopy, and SANS revealing decreasing Tcp in aqueous solution with increasing molar mass, the presence of very few aggregated structures below Tcp, a contraction of the macromolecules at temperatures 5 °C above Tcp but no severe conformational change of the cylindrical structure. In addition, the phase diagram including cloud point and coexistence curve was developed showing an LCST of 75 °C of the binary mixture polyoligo(2‐ethyl‐2‐oxazoline)methacrylate]/water. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013 |
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Keywords: | cloud point comb polymer lower critical solution temperature (LCST) phase diagram poly(2‐oxazoline) small‐angle neutron scattering (SANS) solution properties stimuli sensitive polymers |
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