Abstract
Amphiphiles possessing two equivalent quaternary ammonium groups with one methyl, two dodecyls and a connecting alkanediyl chain of 2 to 20 carbons (m), alkanediyl-α, ω-bis (didodecyl-methylammonium bromide) [Cm-Bis (N-2 C12)], were synthesized.
Determination was made of the phase transition temperature (Tc) of Cm-Bis (N-2 C12) and rate of probe leakage from the vesicles. In Cm-Bis (N-2 C12) /water, Tc decreased with increase in m from 2 to 12 and then increased. The probe leakage (%), however, changed in reverse inclination with respect to m [24<6<8, 10<12, 14>16>20]. The membrane fluidity of vesicles is thus shown closely related to vesicle stability.
The hydrolysis of an amino acid ester was carried out using vesicles of Cm-Bis (N-2 C12) as a hydrolase model. Some tetra-alkylammonium salts showed hydrolyzing activity toward amino acid esters and the activity of C12-Bis (N-2 C12) was greater than that of glycolipid, which was proposed as hydrolase model by the authors.
