Facile, controlled, room-temperature RAFT polymerization of N-isopropylacrylamide.
Poly(N-isopropyl acrylamide) is a thermoresponsive polymer that has been widely investigated for drug delivery. Herein, we report conditions facilitating the controlled, room-temperature RAFT polymerization of N-isopropylacrylamide (NIPAM). The key to success is the appropriate choice of both a suitable RAFT chain transfer agent (CTA) and initiating species. We show that the use of 2-dodecylsulfanylthiocarbonylsulfanyl-2-methyl propionic acid, a trithiocarbonate RAFT CTA, in conjunction with the room-temperature azo initiator 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), in DMF, at 25 degrees C, yields conditions leading to NIPAM homopolymerizations which bear all of the characteristics of a controlled/"living" polymerization. We also demonstrate facile size exclusion chromatographic analysis of PNIPAM samples in DMF at 60 degrees C, directly on aliquots withdrawn during the polymerizations, which avoids the problems previously reported in the literature.
Convertine
Anthony J
AJ
Department of Polymer Science, University of Southern Mississippi, Hattiesburg, Mississippi 39406, USA.
Ayres
Neil
N
Scales
Charles W
CW
Lowe
Andrew B
AB
McCormick
Charles L
CL
D000178:Acrylamides / Q000138:chemical synthesis* / Q000737:chemistry*; D001391:Azo Compounds / Q000737:chemistry; D004126:Dimethylformamide / Q000737:chemistry; D015394:Molecular Structure; D011422:Propionates / Q000737:chemistry; D013696:Temperature
D000178:Acrylamides; D001391:Azo Compounds; D011422:Propionates; D004126:Dimethylformamide; C067295:N-isopropylacrylamide