Structure of polystyrene-block-poly(ethylene oxide) diblock copolymer micelles in water

✍ Scribed by Amane Jada; Guy Hurtrez; Bernard Siffert; Gérard Riess

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 776 KB
• Volume: 197
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.1996.021971117

✦ Synopsis

Abstract

Micellization in water of two homologous series of AB‐type diblock copolymers, composed of polystyrene (PS) as the A block and poly(ethylene oxide) (PEO) as the B block, were investigated by small‐angle X‐ray scattering (SAXS) and dynamic light scattering (DLS). The copolymers have molecular weights M~n~ in the range 2 000—34 800, and have in a given series, the same number of repeating units of the PS block, (N~PS~ = 10 and 38), and a variable number of repeating units of the PEO block (N~PEO~ values in the range 23–704). In order to avoid secondary association of micelles, a dialysis technique was used to prepare the micellar systems, in the case of copolymers having high M~n~ values of the PS block. The experimental micelle properties such as the core radius R~c~ and the aggregation number N of non‐equilibrium structures, so called “frozen micelles”, obtained by dialysis, were found to be independent of the copolymer characteristics. However, for equilibrium structures, obtained by direct solubilization of the copolymers (N~PS~ = 10) in water, R~c~ and N were found to decrease with increasing N~PEO~ for the homologous series.