Authors Zschoche, St. ; Rueda, J.C. ; Binner, M. ; Komber, H. ; Janke, A. ; Arndt, K.-F. ; Lehmann, S. ; Voit, B.
Title Reversibly switchable pH- and thermoresponsive core-shell nanogels based on poly(NiPAAm)-graft-poly(2-carboxyethyl-2-oxazoline)s
Date 24.01.2012
Abstract Amphiphilic graft copolymers with a thermosensitive PNiPAAm backbone and pH-sensitive hydrophilic poly(2-carboxyethyl-2-oxazoline) graft chains are synthesized. In aqueous solution, stable micelle-like aggregates are formed by increasing the temperature in the pH range 4.5–5.5. The micelles are crosslinked by electron-beam irradiation, yielding stable core–shell nanogels of about 100 nm diameter with reversible thermo- and pH-dependent swelling behavior. The temperature sensitivity is provided by a conformational change in the PNiPAAm core, whereas the thickness of the poly(2-carboxyethyl-2- oxazoline) corona depends on pH. The reversible bisensitivity of core-crosslinked nanogels is verified by DLS, while AFM measurements demonstrate the predicted core–shell structures of the aggregates.
Journal Macromolecular Chemistry and Physics 213 (2012) 215-226

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