Εξειδίκευση τύπου :	Άρθρο σε επιστημονικό περιοδικό
Τίτλος:	Surface micelle structures and monolayer compression moduli of double hydrophilic block copolymer
Δημιουργός/Συγγραφέας:	Pan, Wenting Chen, Hongxu Wen, Gangyao Giaouzi, Despoina [EL] Πίσπας, Στέργιος[EN] Pispas, Stergios Zuo, Jintao
Εκδότης:	American Chemical Society
Ημερομηνία:	2020
Γλώσσα:	Αγγλικά
ISSN:	1932-7447 1932-7455
DOI:	10.1021/acs.jpcc.0c05272
Περίληψη:	At the air/water interface, amphiphilic block copolymers are well-known to form typical surface micelles composed of hydrophobic block cores and hydrophilic block coronas. However, the micelle/aggregate structures of the double hydrophilic block copolymers (DHBCs) need to be explored because of the lack of hydrophobic blocks. Influences of subphase pH and temperature on the interfacial aggregation behavior of a thermoresponsive DHBC of poly(N-isopropylacrylamide)-block-poly[oligo(ethylene glycol) acrylate] (PNIPAM-b-POEGA) and the structures of its Langmuir–Blodgett (LB) films were studied with the Langmuir monolayer technique and atomic force microscopy, respectively. All initial LB films of PNIPAM-b-POEGA show circular micelles with a sunflower-like structure composed of a small PNIPAM backbone core, a short amide group shell, and several large POEGA petals, the structure of which is proposed in the DHBCs for the first time. Two kinds of novel methods based on the methylene group number in a core or the core diameter were successfully used to evaluate the micelle structure. With the increase of subphase pH, the isotherms move toward the larger mean molecular areas due to the gradually increased stretching degrees of POEGA blocks at the air/water interface. With the rise in temperature, the limiting molecular areas of the isotherms initially increase and then decrease above the lower critical solution temperature. As compared to those of other copolymers, the maximum monolayer compression moduli of PNIPAM-b-POEGA are very low, which indicates that the DHBC monolayers are highly compressible. Furthermore, at low temperature, hysteresis levels in the continuous compression–expansion cycles decrease stage by stage, whereas those at high temperature change slightly.
Τίτλος πηγής δημοσίευσης:	The Journal of Physical Chemistry C
Τόμος/Κεφάλαιο:	124
Τεύχος:	31
Σελίδες:	17150–17157
Θεματική Κατηγορία:	[EL] Φυσική και θεωρητική χημεία[EN] Physical and theoretical chemistry [EL] Φασματοσκοπία[EN] Spectroscopy
Λέξεις-Κλειδιά:	Copolymers Isotherms Micelles Monolayers Thermoresponsive polymers
Κάτοχος πνευματικών δικαιωμάτων:	Copyright © 2020 American Chemical Society
Ηλεκτρονική διεύθυνση στον εκδότη (link):	https://pubs.acs.org/doi/10.1021/acs.jpcc.0c05272
Ηλεκτρονική διεύθυνση περιοδικού (link) :	https://pubs.acs.org/journal/jpccck
Εμφανίζεται στις συλλογές:	Ινστιτούτο Θεωρητικής και Φυσικής Χημείας (ΙΘΦΧ) - Επιστημονικό έργο