Effects of the fatty acid (
m=846) and alcohol (
n=818) portions in sodium 2-sulfonatofatty acid higher alcohol esters [α-SF : C
mH
2 m+1 CH (SO
3Na] COOC
nH
2 n+1) on the bilayers were investigated with a differential scanning calorimeter (DSC) and small angle X-ray scanning machine (SAXS).
The amount of structural water intercorporated into a coagel phase composed of α-SF molecules was independent of total hydrophobic chain lengths of the surfactants ;
viz., 3 or 4 water molecules per unit α-SF molecule.
Coagel-to-liquid crystalline phase transition (T
c) temperatures of α-SFs increased with an increase in the total hydrophobic chain lengths and/or with a decrease in the difference between two hydrophobic chain lengths. The T
c temperature of α-SFs, in which hydrophobic chain lengths are the same, was closely related to the length in the carbon-bonds of the longer of the two hydrophobic chain lengths (CL).
SAXS indicated the structure of the bilayer of α-SFs to be interdigital. With an increase in the total hydrophobic chain lengths of α-SFs, the lamellar repeat period of α-SFs increased, while those of α-SFs were independent of the difference in length of two hydrophobic chain lenghs.
抄録全体を表示