@article {43375,
	title = {Temperature and pH dual stimuli responsive PCL- b -PNIPAAm block copolymer assemblies and the cargo release studies},
	journal = {Journal of Polymer Science Part A Polymer Chemistry},
	volume = {55},
	year = {2017},
	month = {FEB},
	pages = {1383-1396},
	type = {Article},
	chapter = {1383-1396},
	abstract = {A new atom transfer radical polymerization (ATRP) initiator, namely, 2-(1-(2-azidoethoxy)ethoxy)ethyl 2-bromo-2-methylpropanoate containing both {\textquotedblleft}cleavable{\textquotedblright} acetal linkage and {\textquotedblleft}clickable{\textquotedblright} azido group was synthesized. Well-defined azido-terminated poly(N-isopropylacrylamide)s (PNIPAAm-N3)s with molecular weights and dispersity in the range 11,000{\textendash}19,000 g mol-1 and 1.20{\textendash}1.28, respectively, were synthesized employing the initiator by ATRP. Acetal containing PCL-b-PNIPAAm block copolymer was obtained by alkyne{\textendash}azide click reaction of azido-terminated PNIPAAm-N3 with propargyl-terminated PCL. Critical aggregation concentration (CAC) of PCL-b-PNIPAAm copolymer in aqueous solution was found to be 8.99 {\texttimes} 10-6 M. Lower critical solution temperature (LCST) of PCL-b-PNIPAAm copolymer was found to be 32 {\textdegree}C which was lower than that of the precursor PNIPAAm-N3 (36.4 {\textdegree}C). The effect of dual stimuli viz. temperature and pH on size and morphology of the assemblies of PCL-b-PNIPAAm block copolymer revealed that the copolymer below LCST assembled in spherical micelles which subsequently transformed to unstable vesicles above the LCST. Heating these assemblies above 40 {\textdegree}C led to the precipitation of PCL-b-PNIPAAm block copolymer. Whereas, at decreased pH, micelles of PCL-b-PNIPAAm copolymer disintegrate due to the cleavage of acetal linkage and precipitation of hydrophobic hydroxyl-terminated PCL. The encapsulated pyrene release kinetics from the micelles of synthesized PCL-b-PNIPAAm copolymer was found to be faster at higher temperature and at lower pH. {\textcopyright} 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017},
	doi = {10.1002/pola.28508},
	author = {Patil, Sachin S. and Wadgaonkar, Prakash}
}
