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Preparation of Positively and Negatively Charged Organic Colloids from a Single Precursor
Author(s) -
Röder Thorsten,
Kramer Thomas,
Huber Klaus,
Kitzerow HeinzS.
Publication year - 2003
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200300017
Subject(s) - colloid , dispersity , monomer , polymer chemistry , acrylate , cationic polymerization , methacrylate , chemistry , polyelectrolyte , charge density , chemical engineering , aqueous solution , trimethylamine , materials science , polymer , organic chemistry , physics , quantum mechanics , engineering
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.