Effect of alkane chain length and counterion on the freezing transition of cationic surfactant adsorbed film at alkane mixture - water interfaces.
Penetration of alkane molecules into the adsorbed film gives rise to a surface freezing transition of cationic surfactant at the alkane-water interface. To examine the effect of the alkane chain length and counterion on the surface freezing, we employed interfacial tensiometry and ellipsometry to study the interface of cetyltrimethylammonium bromide and cetyltrimethylammonium chloride aqueous solutions against dodecane, tetradecane, hexadecane, and their mixtures. Applying theoretical equations to the experimental results obtained, we found that the alkane molecules that have the same chain length as the surfactant adsorb preferentially into the surface freezing film. Furthermore, we demonstrated that the freezing transition temperature of cationic surfactant adsorbed film was independent of the kind of counterion.
†Department of Chemistry, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan.
Yuhei
Y
Tokiwa
‡Department of Visual Communication Design, Faculty of Design, Kyushu University, Fukuoka 815-8540, Japan.
Hiroyasu
H
Sakamoto
§Faculty of Arts and Sciences, Kyushu University, Fukuoka 819-0395, Japan.
Takanori
T
Takiue
†Department of Chemistry, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan.
Makoto
M
Aratono
†Department of Chemistry, Faculty of Sciences, Kyushu University, Fukuoka 812-8581, Japan.
Hiroki
H
Matsubara