Aggregation behaviors of a polystyrene-b-poly(methyl methacrylate) diblockcopolymer at the air/water interface

Citation
Y. Seo et al., Aggregation behaviors of a polystyrene-b-poly(methyl methacrylate) diblockcopolymer at the air/water interface, MACROMOLEC, 34(14), 2001, pp. 4842-4851
Citations number
47
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
MACROMOLECULES
ISSN journal
0024-9297 → ACNP
Volume
34
Issue
14
Year of publication
2001
Pages
4842 - 4851
Database
ISI
SICI code
0024-9297(20010703)34:14<4842:ABOAPM>2.0.ZU;2-#
Abstract
Aggregation behaviors, in particular, surface micelle formation, of a diblo ck copolymer A-B, where the A block is polystyrene (PS, surface inactive an d water insoluble) and the B block is poly(methyl methacrylate) (PMMA, surf ace active, but water insoluble), at the airwater interface have been exami ned. The block length ratio of PS:PMMA was 140K:646K. With the aid of a Lan gmuir film balance and an atomic force microscope (AFM), surface pressure i sotherms, as well as the hysteresis and temperature effects on the isotherm s and aggregation numbers, were determined, and a self-consistent picture o f the surface morphology and the aggregation phenomena was obtained. Analog ous to the critical micelle concentration in a bulk solution of a surfactan t, the surface aggregation of the block copolymer took place only at a cert ain surface mass density and resulted in small circular micelles with an ag gregation number around 6-7, as determined by AFM. The small aggregation nu mber is attributed to the longer block length of PMMA relative to that of P S.