Preparation of Positively and Negatively Charged Organic Colloids from a Single Precursor

✍ Scribed by Thorsten Röder; Thomas Kramer; Klaus Huber; Heinz-S. Kitzerow

• Book ID: 102485614
• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: English
• Weight: 169 KB
• Volume: 204
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/macp.200300017

✦ Synopsis

Abstract

A synthetic route is presented for the preparation of electrically charged colloidal particles with either sign from the same precursor. In the first step, methyl methacrylate was copolymerized with ω‐bromoalkyl acrylate and a cross‐linker, leading to monodisperse, bromo‐functionalized colloids. Substitution of the bromo‐functions by either trimethylamine or Na~2~SO~3~ transformed the neutral precursors into positively or negatively charged particles, respectively. The charge density could be varied in two ways: (i) by varying the fraction of bromo‐functionalized monomers; (ii) by increasing the degree of substitution of the bromo‐functions. Derivation of the charged particles from the same precursor colloid made it easier to explain various interesting physical properties of the charged colloidal particles. Higher charge densities were achieved for the cationic colloids. If a threshold value for the charge density of 55 μC · cm^−2^ was surpassed, the particles showed a significant swelling in aqueous solution.
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