ISSN:
0887-624X
Schlagwort(e):
synthesis
;
homopolymerization
;
block copolymerization
;
N-ethyl-2-ethyl-pyridinium
;
Chemistry
;
Polymer and Materials Science
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
A novel acetylenic monomer 2-N-ethyl pyridinium trifluoromethane sulfonate (2EPyEtTf) was synthesized and polymerized. Diblock copolymers of 2EPyEtTf with styrene and with butadiene were prepared. Initiation of the polymerization by living anionic polystyryl--Li+ and polybutadienyl--Li+ (Scheme 1) resulted in polystyrene-block-poly(N-ethyl-2-ethynylpyridinium trifluoromethanesulfonate) (PS57PA8), and polybutadiene -block-poly(N-ethyl-2-ethynylpyridinium trifluoromethanesulfonate) (PB30PA8). These amphiphilic block molecules contain rigid, conjugated, and strongly hydrophilic polyacetylene chain fragments attached to hydrophobic polystyrene or flexible polybutadiene chain fragments. The structure of these copolymers was studied by FTIR, UV-visible, and NMR spectroscopy. GPC and viscometry were also used to obtain information on the molecular mass and the molecular mass distribution. Thermal behavior was investigated by means of TGA and DSC. Both block copolymers were shown to form stable monolayers at the air-water interface. The positively charged rigid polyacetylene portion of the copolymer is believed to be partially submerged, while the more flexible hydrophobic chains are forced out of the water. Multilayers of PB30PA8 deposited using the Langmuir-Blodgett technique were found to be less uniform than in the case of the previously reported polystyrene-block-poly(2EPyMeTf) (PS12PA4) copolymer (Balogh et al., Macromolecules, 29, 1996). Polycation-polyanion self-assembly deposition was also investigated, using polystyrenesulfonate (PSS) as polyanion. While PS57PA8/PSS layer-by-layer deposition was not uniform, it was found that PB30PA8/PSS gave homogenous and stable films on hydrophilic glass substrates. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 703-712, 1998
Zusätzliches Material:
8 Ill.
Materialart:
Digitale Medien
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