Journal
POLYMER
Volume 44, Issue 3, Pages 509-518Publisher
ELSEVIER SCI LTD
DOI: 10.1016/S0032-3861(02)00811-X
Keywords
amphiphilic block copolymers; atom transfer radical polymerization; emulsion polymerization
Categories
Ask authors/readers for more resources
A series of diblock, triblock and star-block copolymers composed of polystyrene and poly(acrylic acid) were synthesized by ATRP. The structure of the copolymers, the size of the blocks and the composition were varied, keeping however a short polystyrene block and a poly(acrylic acid) content larger than 60 mol% to allow solubility in alkaline water. Their micellization was studied by static and dynamic light scattering and the influence of their structural characteristics on the aggregation number, N-agg, was examined at low salt concentration and alkaline pH. It was shown that micelles were in thermodynamic equilibrium and that Nagg followed the power law N-agg similar to (NA-0.9NS2) (with N-A, the total number of acrylic acid units in the copolymer and N-S, the total number of styrene units), that is characteristic of amphiphile micelles formed from strongly segregated block copolymers. Moreover, N-agg was independent of salt concentration in the investigated range. The same copolymers were previously used as stabilizers in emulsion polymerization [Macromolecules 34 (2001) 4439]. The final latex particle concentration, N-p, was compared with N-m, the initial micelle concentration. This enabled us to conclude that among the block copolymers studied, those with high acid content behaved like low molar mass surfactants. In contrast, those with low acid content formed stable micelles that could be directly nucleated to create latex particles, allowing a good control over N-p. (C) 2002 Elsevier Science Ltd. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available