Synthesis and aqueous solution properties of novel anionic heterogemini surfactants containing a phosphate headgroup.
The physicochemical properties of aqueous solutions of novel anionic heterogemini surfactants (POH-n-ODAm) have been studied on the basis of static/dynamic surface tension, fluorescence, dynamic light scattering (DLS) and cryogenic transmission electron microscope (cryo-TEM) data. The surfactants are synthesized from oleic acid: the hydrocarbon chain (n=6, 8 and 10) is covalently bound to the terminal carbonyl group and a phosphate headgroup is introduced to the cis double bond of an oleic acid derivative. The static surface tension and fluorescence measurements demonstrate that the critical aggregation concentration (cac) is decreased significantly with increasing hydrocarbon chain length, resulting from the increased hydrophobicity and the increased degree of dissymmetry of the surfactants. As is generally seen for gemini surfactants, the measured cac is much lower than that of the monomeric phosphate-type surfactant reported previously. At concentrations well above the cac, the heterogemini surfactants spontaneously form vesicular assemblies in bulk solution, which is confirmed with DLS and cryo-TEM measurements.
Takamatsu
Yuichiro
Y
Miyoshi Oil & Fat Co., Ltd., 4-66-1 Horikiri, Katsushika, Tokyo 124-8510, Japan.
Iwata
Naoyuki
N
Tsubone
Kazuyuki
K
Torigoe
Kanjiro
K
Endo
Takeshi
T
Sakai
Kenichi
K
Sakai
Hideki
H
Abe
Masahiko
M