H. Otsuka et K. Esumi, INTERACTION BETWEEN POLY(N-VINYL-2-PYRROLIDONE) AND ANIONIC HYDROCARBON FLUOROCARBON SURFACTANT ON HYDROPHOBIC GRAPHITE/, Journal of colloid and interface science, 170(1), 1995, pp. 113-119
The adsorption of poly(N-vinyl-2-pyrrolidone) (PVP), lithium dodecyl s
ulfate (LiDS), and lithium perfluorooctanesulfonate (LiFOS) from PVP-L
iDS and PVP-LiFOS binary mixed solutions on hydrophobic graphite has b
een investigated by measuring the adsorbed amount, ESR spectra, and ze
ta potential. The adsorption of PVP is enhanced in the presence of LiD
S at low LiDS concentration due to formation of a surface complex of P
VP and LiDS, followed by a decrease at high LiDS concentration. Howeve
r, this increment on hydrophobic graphite is significantly smaller tha
n that on hydrophilic alumina. A similar trend is observed in the PVP-
LiFOS system. In both PVP-LiDS and PVP-LiFOS systems, the conformation
of PVP adsorbed is estimated using a spin-labeled PVP and is changed
gradually from loops and tails to trains with the surfactant concentra
tion. The fraction of train segments in the PVP-LiFOS system is greate
r than that in the PVP-LiDS system over the whole surfactant concentra
tion region. (C) 1995 Academic Press, Inc.