Authors
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Reihs, T. ; Müller, M. ; Lunkwitz, K.
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Title
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Preparation and adsorption of refined polyelectrolyte complex nanoparticles
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Date
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16.02.2004
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Number
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12093
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Abstract
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We report on bulk and surface properties of centrifuged nonstoichiometric polyelectrolyte complex (PEC) dispersions. PECs were prepared by mixing poly(diallyldimethylammonium chloride) (PDADMAC) and sodium poly(maleic acid-co-α-methylstyrene) (PMA-MS) at the monomolar mixing ratio of 0.6 and polymer concentration <img src="http://www.sciencedirect.com/scidirimg/entities/ges.gif" alt="gt-or-equal, slanted" border=0>1 mmol/l. Centrifugation of initial PEC dispersions revealed three phases: supernatant (SUP), coacervate (COAC), and an insoluble precipitate. Mass, turbidity, particle hydrodynamic radii (<i>R</i><sub><i>h</i></sub>), and the titratable charge amount were determined for those phases. The turbid COAC phase consisted of 200-nm nanoparticles and carried 60% of the polymer mass and 20% of the titratable charge amount of the initial PEC dispersion. The SUP phase showed no turbidity and no such nanoparticles, but carried 80% of the initial titratable charge amount, presumably caused by excess polycations. Furthermore, linear dependences of turbidity and <i>R</i><sub><i>h</i></sub> on COAC concentration was observed. COAC adsorption was studied at polyelectrolyte multilayer (PEM) modified silicon surfaces in dependence on both adsorption time and concentration using attenuated total-reflection–Fourier transform infrared (ATR–FTIR) spectroscopy. The adsorption data were fitted by the simple Langmuir model. Comparison of COAC particles an<br />d polystyrene latices revealed similar adsorption features. SEM and AFM measurements resulted in hemispherically shaped adsorbed COAC particles with coverages <img src="http://www.sciencedirect.com/scidirimg/entities/ges.gif" alt="gt-or-equal, slanted" border=0>25%, whose calculated volumes correlated well with those in dispersion obtained by PCS.
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Publisher
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Journal of Colloid and Interface Science
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Wikidata
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Citation
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Journal of Colloid and Interface Science 271 (2004) 69-79
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DOI
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https://doi.org/10.1016/j.jcis.2003.11.019
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Tags
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