A new strategy to prepare temperature-sensitive poly(N-isopropylacrylamide) microgels
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In this study, a new method was developed to prepare temperature-sensitive poly(N-isopropylacrylamide) microgels by free radical precipitation polymerization using siloxane coupling agent as the new crosslinker. Ammonium persulfate acted as the initiator for the radical copolymerization as well as the catalyst for the hydrolysis/condensation of the siloxane groups. The particle diameter and polydispersity of the microgels were measured by photon correlation spectroscopy and the results display that the microgels are monodisperse. The microgels exhibit temperature sensitivity and the phase transition temperature is approximately 31 °C. Furthermore, the diameter of the microgels changes upon heating and cooling processes. These were observed to be reversible. The novel crosslinking method described herein is the condensation of siloxane groups, which is totally different from the traditional double-vinyl crosslinkers. This innovative approach offers an alternative path to prepare functional core–shell particles and inorganic/organic hybrid materials.
KeywordsMicrogel Temperature sensitive Poly(N-isopropylacrylamide) Siloxane coupling agent
J.T. gratefully acknowledges the financial support in form of an Alexander-von-Humboldt Fellowship from the Alexander-von-Humboldt Foundation, Bonn, Germany. The authors also acknowledge the partial financial support of the BMBF for this work within the project “Innovations- und Gründerlabor für neue Werkstoffe (Biomaterialien) und Verfahren (IGWV) an der Friedrich-Schiller-Universität Jena” Förderkennzeichen: 03GL0026. J.T.Z. and K.D.J. are grateful to Karin Jandt for proofreading the manuscript.