L. Balogh et al., SYNTHESIS, HOMOPOLYMERIZATION, AND BLOCK COPOLYMERIZATION OF N-ETHYL-2-ETHYNYL-PYRIDINIUM TRIFLUOROMETHANESULFONATE WITH STYRENE AND BUTADIENE, Journal of polymer science. Part A, Polymer chemistry, 36(5), 1998, pp. 703-712
A novel acetylenic monomer 2-N-ethyl pyridinium trifluoromethane sulfo
nate (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 polybutadi
enyl(-)-Li+ (Scheme 1) resulted in polystyrene-block-poly(N-ethyl-2-et
hynylpyridinium trifluoromethanesulfonate) (PS(57)PA(8)), and lybutadi
ene-block-poly(N-ethyl-2-ethynylpyridinium trifluoromethanesulfonate)
(PB(30)PA(8)). These amphiphilic block. molecules contain rigid, conju
gated, 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, an
d NMR spectroscopy. GPC and viscometry were also used to obtain inform
ation on the molecular mass and the molecular mass distribution. Therm
al behavior was investigated by means of TGA and DSC. Both block copol
ymers were shown to form stable monolayers at the air-water interface.
The positively charged rigid polyacetylene portion of the copolymer i
s believed to be partially submerged, while the more flexible hydropho
bic chains are forced out of the water. Multilayers of PB(30)PA(8) dep
osited using the Langmuir-Blodgett technique were found to be less uni
form than in the case of the previously reported polystyrene-bloch-pol
y (2EPyMeTf)(PS(12)PA(4)) copolymer (Balogh et al., Macromolecules, 29
, 1996). Polycation-polyanion self-assembly deposition was also invest
igated, using polystyrenesulfonate (PSS) as polyanion. While PS(57)PA(
8)/PSS layer-by-layer deposition was not uniform, it was found that PB
(30)PA(8)/PSS gave homogenous and stable films on hydrophilic glass su
bstrates. (C) 1998 John Wiley & Sons, Inc.