Εξειδίκευση τύπου :	Άρθρο σε επιστημονικό περιοδικό
Τίτλος:	Thermo-Induced Aggregation Behavior of Poly(ethylene oxide)-b-poly(N-isopropylacrylamide) Block Copolymers in the Presence of Cationic Surfactants
Δημιουργός/Συγγραφέας:	Zhao, Junpeng Zhang, Guangzhao [EL] Πίσπας, Στέργιος[EN] Pispas, Stergios
Εκδότης:	American Chemical Society
Τόπος έκδοσης:	WASHINGTON
Ημερομηνία:	2009-08-06
Γλώσσα:	Αγγλικά
ISSN:	1520-6106
DOI:	10.1021/jp9038896
Περίληψη:	Low-molecular-weight cationic surfactants, dodecyltrimethylammonium bromide (DTAB) and cetyltrimethylammonium bromide (CTAB), were introduced to dilute aqueous solutions of thermosensitive poly(ethylene oxide)-b-poly(N-isopropylacrylamide) (PEO-b-PNIPAM) block copolymers at concentrations (C(s)) either lower or higher than the critical micelle concentrations (cmc) of the surfactants. The copolymer/surfactant mixtures were investigated by dynamic and static light scattering at different temperatures. At temperature lower than the aggregation temperature (T(agg)), the disaggregation of the copolymers from the loose associations was observed upon addition of the surfactants. The thermo-induced aggregation behavior was found to be profoundly influenced with the cooperation of cationic surfactants in terms of T(agg) and the structural characteristics of the aggregates formed at high temperature. In general, T(agg) was increased together with the decrease in the size and molecular weight of the aggregates. These were attributed to the copolymer/surfactant interactions and the electrostatic repulsion coming from the ionic head groups of the surfactants within the mixed aggregates. These changes were much more pronounced at higher C(s). CTAB, which has a longer hydrophobic tail, displayed higher influences compared to DTAB. The formation of vesicles, by one of the copolymers, was suppressed in the presence of CTAB. At the higher CTAB concentration, only small mixed aggregates with very low mass were observed even at the highest temperature investigated.
Τίτλος πηγής δημοσίευσης:	Journal of Physical Chemistry B
Τόμος/Κεφάλαιο:	113
Τεύχος:	31
Σελίδες:	10600-10606
Θεματική Κατηγορία:	[EL] Φυσική και θεωρητική χημεία[EN] Physical and theoretical chemistry
Αξιολόγηση από ομότιμους (peer reviewed):	Ναι
Κάτοχος πνευματικών δικαιωμάτων:	© AMER CHEMICAL SOC
Ηλεκτρονική διεύθυνση περιοδικού (link) :	http://www.pubs.acs.org/jpcb
Εμφανίζεται στις συλλογές:	Ινστιτούτο Θεωρητικής και Φυσικής Χημείας (ΙΘΦΧ) - Επιστημονικό έργο