DSC investigations of DDAB, DTAB and DHAB vesicle aqueous solutions in presence of SDS

Interactions of anionic surfactant sodium dodecyl sulphate (SDS) with vesicles formed by synthetic dialkyldimethylammonium bromides i.e. didodecyldimethylammonium bromide (DDAB), ditetradecyldimethylammonium bromide (DTAB), dihexadecyldimethylammonium bromide (DHAB) have been examined by using differential scanning microcalorimetry and electron transmission microscopy. The temperatures and standard enthalpies characterising gel to liquid-crystal transitions increase significantly with increase of SDS concentration for all investigated systems. It means that incorporation of SDS monomers in these vesicular bilayers significantly stabilises their gel states. Moreover, in case of DDAB and DTAB vesicle systems added SDS limits kinetic features of recorded isobaric heat capacity dependencies on temperature observed earlier for the pure vesicular solutions.