Εξειδίκευση τύπου :	Άρθρο σε επιστημονικό περιοδικό
Τίτλος:	Morphological Transitions in Aggregates of Thermosensitive Poly(ethylene oxide)-b-poly(N-isopropylacrylamide) Block Copolymers Prepared via RAFT Polymerization
Δημιουργός/Συγγραφέας:	Zhao, Junpeng Zhang, Guangzhao [EL] Πίσπας, Στέργιος[EN] Pispas, Stergios
Εκδότης:	John Wiley & Sons, Inc.
Τόπος έκδοσης:	HOBOKEN
Ημερομηνία:	2009-08-15
Γλώσσα:	Αγγλικά
ISSN:	0887-624X
DOI:	10.1002/pola.23470
Περίληψη:	Double hydrophilic poly(ethylene oxide)-b-poly(N-isopropylacrylamide) (PEO-b-PNIPAM) block copolymers were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization, using a PEO-based chain transfer agent (PEO-CTA). The molecular structures of the copolymers were designed to be asymmetric with a short PEO block and long PNIPAM blocks. Temperature-induced aggregation behavior of the block copolymers in dilute aqueous solutions was systematically investigated by a combination of static and dynamic light scattering. The effects of copolymer composition, concentration (CP), and heating rate on the size, aggregation number, and morphology of the aggregates formed at temperatures above the LCST were studied. In slow heating processes, the aggregates formed by the copolymer having the longest PNIPAM block, were found to have the same morphology (spherical "crew-cut" micelles) within the full range of C, Nevertheless, for the copolymer having the shortest PNIPAM block, the morphology of the aggregates showed a great dependence on CP. Elongation of the aggregates from spherical to ellipsoidal or even cylindrical was observed. Moreover, vesicles were observed at the highest C(p) investigated. Fast heating leads to different characteristics of the aggregates, including lower sizes and aggregation numbers, higher densities, and different morphologies. Thermodynamic and kinetic mechanisms were proposed to interpret these observations, including the competition between PNIPAM intrachain collapse and interchain aggregation.
Τίτλος πηγής δημοσίευσης:	Journal of Polymer Science Part A-polymer Chemistry
Τόμος/Κεφάλαιο:	47
Τεύχος:	16
Σελίδες:	4099-4110
Λέξεις-Κλειδιά:	light scattering RAFT self-assembly thermosensitive block copolymers Polymer Science
Αξιολόγηση από ομότιμους (peer reviewed):	Ναι
Κάτοχος πνευματικών δικαιωμάτων:	© 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4099-4110, 2009
Ηλεκτρονική διεύθυνση περιοδικού (link) :	http://www3.interscience.wiley.com/cgi-bin/jhome/36444
Εμφανίζεται στις συλλογές:	Ινστιτούτο Θεωρητικής και Φυσικής Χημείας (ΙΘΦΧ) - Επιστημονικό έργο