Physicochemical Properties of 2-Vinylpyridine Telomers Possessing Multihydrocarbon Chains in Aqueous Solution and at the Silica/Aqueous Solution Interface.
Physicochemical properties of multialkylated surfactants of partially quaternized 2-vinylpyridine telomers having multihydrocarbon side chains (nRm-2VPQ: n, number of chains; m, alkyl chain length) in aqueous solutions were investigated. The critical micelle concentration (cmc) and surface tension at the cmc were 13 µmol dm(-3) and 52 mNm(-1) for 2.1R(8)-2VPQ, 7.1 µmol dm(-3) and 37 mNm(-1) for 2.5R(12)-2VPQ, and 4.7 µmol dm(-3) and 40.0 mNm(-1) for 3.4R(12)-2VPQ, respectively. The aggregation numbers at the cmc determined by the light scattering method were 4 +/- 1 for 2.1R(8)-2VPQ, 45 +/- 10 for 2.5R(12)-2VPQ, and 11 +/- 1 for 3.4R(12)-2VPQ. Thus, the number of chains and the alkyl chain length of the telomers affected the micellar properties in aqueous solutions. At the interface of the silica/aqueous solution, the adsorbed amounts of the telomers increased sharply at their low concentrations and reached a plateau by forming a monolayer and a subsequent bilayer. Silica suspensions also showed a dispersion-flocculation-redispersion sequence with the telomer concentration, where the maximum sedimentation rate was influenced by the number of chains and the alkyl chain length of the telomers. Copyright 1999 Academic Press.
Esumi
K
Institute of Colloid and Interface Science, Science University of Tokyo, Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan
Mizutani
H
Shoji
K
Miyazaki
M
Torigoe
K
Yoshimura
T
Koide
Y
Shosenji
H