Spontaneous Formation of Vesicles by N-Alkyl-N-Methylmorpholinium Bromide and Sodium Dodecyl Sulfate (SDS)

The formation of vesicles, composed of N-alkyl-N-methylmorpholinium bromide ([Mor(1,12)]Br) and sodium dodecyl sulfate (SDS), is investigated. The phase diagram of the mixed surfactant aqueous solutions is determined through visual observation and electrical conductivity measurements. The formation of vesicles is confirmed in the lamellar phase (La) through Cryo-TEM. The irregular shape of vesicles is observed successfully in micrographs. Moreover, the rheological properties, size distribution and zeta potential in different mole ratio are studied. The behavior of the vesicle solution matches Bingham fluid in rheological tests. With the mole ratio r increases, the average size increases while the zeta-potential value decreases. Electrostatic and hydrophobic interactions are regarded as the main driving forces for the formation of vesicles.