299. Xu, Y.; Bolisetty, S.; Drechsler, M.; Fang, B.; Yuan, J.; Ballauff, M.; Müller, A.H.E.: pH and Salt Responsive Poly(N,N-dimethylaminoethyl methacrylate) Cylindrical Brushes and their Quaternized Derivatives, Polymer 49, 39573964 (2008) -- DOI: 10.1016/j.polymer.2008.06.051 -- PDF | |
Stichworte: PDMAEMA, PMETAI, ATRP, polyelectrolytes, cylindrical polymer brushes, pH responsive, cryo-TEM, AFM, DLS | |
Abstract: We present the synthesis and characterization of poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) cylindrical brushes, their pH responsiveness, and the corresponding quaternized analog, poly{[2-(methacryloyloxy)ethyl] trimethylammonium iodide} (PMETAI) brushes. PDMAEMA brushes were prepared by Atom Transfer Radical Polymerization (ATRP) using the grafting-from strategy. Initiating efficiencies of the ATRP processes were determined by cleaving the side-chains and gel permeation chromatography (GPC) analysis. Due to the slow initiation and steric hindrance, the initiating efficiency is only around 50%. The PDMAEMA brushes show worm-like structures and pH responsiveness, as proven by dynamic light scattering (DLS), atomic force microscopy (AFM), and cryogenic transmission electron microscopy (cryo-TEM) measurements. Strong cationic polyelectrolyte PMETAI brushes were produced by quaternization of the PDMAEMA brushes. AFM and cryo-TEM images showed similar worm-like morphologies for the PMETAI brushes. The PMETAI brushes collapsed in solution with high concentration of monovalent salt, as proven by DLS and AFM results. |
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- Projekt: SFB 481 TP A12: Überstrukturbildung und Phasengleichgewichte in konzentrierten Lösungen von geladenen Sternpolymeren