This work aimed to
study the solvation properties of newly synthesized
cationic surfactants: 1-hexyl-1-methyl-1H-imidazol-1-ium
bromide (R6Im), 1-dodecyl-1-methyl-1H-imidazol-1-ium
bromide (R12Im), N,N,N-tributylhexan-1-aminium bromide (R6N4), and N,N,N-tributyldodecan-1-aminium
bromide (R12N4) in water and ethanol–water
solvents with a 0.237 mole fraction of ethanol at 298.15 K using conductivity,
refractive index, surface tension, and density measurements. Critical
micelle concentration (CMC) for the synthesized surfactants was determined
and discussed. Thermodynamic parameters including association constant,
molal volume, and polarizability were calculated and discussed. Some
surface properties of surfactants including excess surface concentration
and minimum area per molecule were also calculated and discussed.
A good agreement was found between the CMC values obtained from different
techniques, such as conductivity, refractive index, and surface tension.
Imidazolium surfactants had been proved to decrease the CMC and increase
the association constant with the increase of ethanol mole fraction,
while tributylamine had been proved to increase the CMC and decrease
the association constant with the increase of ethanol mole fraction.
Also, imidazolium surfactants had been proved to have higher CMC than
tributylamine, which may be related to higher solvation of imidazolium
surfactants than that of tributylamine. Both surfactants (R12Im) and (R12N4) were proved to have lesser
CMC.