LCST and UCST in one : Double thermoresponsive behavior of block copolymers of poly(ethylene glycol) and poly(acrylamide-co-acrylonitrile)

Titelangaben

Käfer, Florian ; Liu, Fangyao ; Stahlschmidt, Ullrich ; Jérôme, Valérie ; Freitag, Ruth ; Karg, Matthias ; Agarwal, Seema:
LCST and UCST in one : Double thermoresponsive behavior of block copolymers of poly(ethylene glycol) and poly(acrylamide-co-acrylonitrile).
In: Langmuir. Bd. 31 (2015) Heft 32 . - S. 8940-8946.
ISSN 1520-5827
DOI: https://doi.org/10.1021/acs.langmuir.5b02006

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Abstract

The change in thermoresponsive behavior from a single phase transition of UCST-type of an acrylamide-acrylonitrile copolymer (AAm-co-AN) to a double responsive behavior (LCST-UCST-type) in water by the introduction of a poly(ethylene glycol) (PEG) block is highlighted in the present work. The polymer is synthesized in a simple way by free-radical polymerization of acrylamide and acrylonitrile using a poly(ethylene glycol) (PEG) macro-azoinitiator. The dual thermoresponsive behavior was observed in a wide range of concentration repeatable for many cycles with very small hysteresis. Static light scattering (SLS) and dynamic light scattering (DLS) together with turbidity photometry and transmission electron microscopy confirmed a unique phase transition behavior due to the temperature dependent change in the morphology from micelles to agglomerates and back to micelles. The low cytotoxicity and two-in-one thermoresponsive behavior makes the polymer promising for biomedical applications in the future.