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Synthesis and characterization of star-shaped Poly(N,N-dimethylaminoethyl methacrylate) and its quaternized ammonium salts

Title data

Plamper, Felix A. ; Schmalz, Alexander ; Penott-Chang, Evis Karina ; Drechsler, Markus ; Jusufi, Arben ; Ballauff, Matthias ; Müller, Axel H. E.:
Synthesis and characterization of star-shaped Poly(N,N-dimethylaminoethyl methacrylate) and its quaternized ammonium salts.
In: Macromolecules. Vol. 40 (7 August 2007) Issue 16 . - pp. 5689-5697.
ISSN 0024-9297
DOI: https://doi.org/10.1021/ma070452x

Official URL: Volltext

Abstract in another language

We report on the synthesis and characterization of star-shaped strong polyelectrolytes and their precursor stars with up to 24 arms. To achieve this we polymerized 2-(N,N-dimethylamino)ethyl methacrylate (DMAEMA) by atom transfer radical polymerization employing a core-first attempt. Sugar-based scaffolds as well as silsesquioxane nanoparticles were used as oligofunctional initiators. Subsequent quaternization of the obtained poly(DMAEMA) stars yielded star-shaped poly{2-(methacryloyloxy)ethyl] trimethylammonium iodide} (PMETAI). The initiation site efficiency was determined both by molecular weight measurements of the cleaved arms and by a statistical method after partial destruction of the inorganic core. The rather low efficiency of the initiation sites (30-75%) leads to a moderate arm number distribution of the prepared polyelectrolyte stars. As expected, the hydrodynamic radii of these polyelectrolyte stars decrease with increasing ionic strength. However, if the ionic strength was adjusted with NaI instead of NaCl, pronounced ion-specific effects were observed; the star polyelectrolyte first strongly shrinks with increasing salt concentration and becomes insoluble at about 0.5 M NaI (''salting out''). Still higher concentrations of NaI lead to a redissolution and a reswelling of the star polyelectrolyte (''salting in''). The measured osmotic coefficients are low and decrease with increasing arm number from phi similar to 0.12 for a 3-arm star down to phi similar to 0.04 for an 18-arm star, confirming the expected strong counterion confinement within these objects with high charge density.

Further data

Item Type: Article in a journal
Refereed: Yes
Additional notes: ISI:000248439700011
Keywords: TRANSFER RADICAL POLYMERIZATION; SPHERICAL POLYELECTROLYTE BRUSHES; OSMOTIC COEFFICIENT; CYCLODEXTRIN-CORE; MODEL NETWORKS; POLYMERS; ATRP; COPOLYMERS; CONFORMATION; ARCHITECTURE
Institutions of the University: Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Chair Macromolecular Chemistry II
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Chair Macromolecular Chemistry II > Chair Macromolecular Chemistry II - Univ.-Prof. Dr. Andreas Greiner
Profile Fields > Advanced Fields > Polymer and Colloid Science
Research Institutions > Research Centres > Bayreuth Center for Colloids and Interfaces - BZKG
Faculties
Faculties > Faculty of Biology, Chemistry and Earth Sciences
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry
Profile Fields
Profile Fields > Advanced Fields
Research Institutions
Research Institutions > Research Centres
Result of work at the UBT: Yes
DDC Subjects: 500 Science > 540 Chemistry
Date Deposited: 15 Apr 2015 09:02
Last Modified: 09 Jun 2015 11:49
URI: https://eref.uni-bayreuth.de/id/eprint/10395