Expulsion of Unimers from Polystyrene-block-poly(acrylic acid) Micelles

✍ Scribed by Lichao Gao; Linqi Shi; Wangqing Zhang; Yingli An; Xiaowei Jiang

• Book ID: 102488107
• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 237 KB
• Volume: 207
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.200500496

✦ Synopsis

Abstract

Summary: The pH response of the micelles of polystyrene‐block‐poly(acrylic acid) (PS~200~‐b‐PAA~78~) in water is studied using a combination of techniques: static light scattering (SLS), dynamic light scattering (DLS), and transmission electron microscopy (TEM). The structure of the micelles in dilute aqueous solution is dependent on pH. At pH values <2.5, the micelles precipitate. At pH values from 2.5 to 3.5, the micelles associate to form micellar clusters. At pH values ranging from 3.5 to 8.0, the micelles are dynamically frozen. At pH > 8.1, some PS~200~‐b‐PAA~78~ unimers gradually escape from the micelles and subsequently re‐associate to form smaller micelles.

The pH‐responsive behavior of the PS~200~‐b‐PAA~78~ micelles in solution.

magnified imageThe pH‐responsive behavior of the PS~200~‐b‐PAA~78~ micelles in solution.