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Authors
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Ouyang, W. ; Müller, M. ; Keßler, B. ; Richter, S.
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Title
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Monomodal polyelectrolyte complex nanoparticles: Preparation by consecutive centrifugation and protein interaction
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Date
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28.06.2007
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Number
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14786
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Abstract
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PMSE 215 - The 233rd ACS National Meeting, Chicago, IL, March 25-29, 2007<br /><br />Herein we report on the refinement of anionic and cationic nanoparticles of nonstoichometric polyelectrolyte complexes (PEC) by consecutive centrifugation, which was studied by dynamic light scattering (DLS), atomic force microscopy (AFM), colloid titration and infrared spectroscopy (IR). PEC dispersions were prepared by mixing polycations like PDADMAC and polyanions like copolymers of maleic acid (PMA-X) or poly(styrenesulfonate) (PSS) at the monomolar mixing ratio of n-/n+ = 1.50 (anionic PEC) and 0.66 (cationic PEC), respectively, and defined polymer concentrations. The particle size (Rh), titrable charge amount and IR spectra were determined in the original state, after first centrifugation and after second centrifugation of the dispersions. Freshly prepared PEC dispersions contained excess polyelectrolyte, small primary complexes and aggregated PEC particles. Consecutive centrifugation of freshly prepared PEC dispersions resulted in the separation of these compounds and the formation of monomodal PEC particles sizing around 100 nm found by DLS. These results were supported by AFM measurements on the respective dispersions deposited on glass plates. Anionic PEC-1.50 particles tended to adopt slightly smaller sizes (» 90 nm) in comparison to cationic PEC-0.66 ones (» 110 nm). IR spectroscopy showed changes in the environment of the carboxylate groups of maleic acid copolymers by consecutive centrifugation and gave evidence on the effective stoichometric ratio of anionic and cationic monomer units. We assume, that the obtained low polydispersity is due to an accelerated colloid ripening process due to Ostwald and the high macroscopic stability is due to repulsive electrostatic interparticle interactions and attractive hydrophobic intraparticle interaction. These monomodal PEC particles migh be projected as latex analogues or nanocarriers for drugs and proteins. Finally, results on their interaction with model proteins are included.
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Publisher
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Polymeric Materials: Science and Engineering
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Wikidata
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Citation
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Polymeric Materials: Science and Engineering 96 (2007) 352-353
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DOI
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http://oasys2.confex.com/acs/233nm/techprogram/P1031520.HTM
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