The formation of a variety of mixed colloidal aggregates has been investigated on a ternary ionic−nonionic system constituted by (i) a double-chain cationic surfactant with a 12-carbon atom hydrophobic
tail, didodecyldimethylammonium bromide (di-C12DMAB), (ii) a nonionic single-chain surfactant, octyl-β-d-glucopyranoside (OBG), and (iii) water. The study has been carried out by means of conductivity,
ζ-potential, transmission electron microscopy (TEM), and cryogenic transmission electron microscopy
(cryo-TEM) experiments on the highly diluted, very diluted, and moderately diluted regions. The formation
of mixed microaggregates, prior to the appearance of mixed vesicles, has been undoubtly confirmed by
conductivity, TEM, and ζ-potential results. The concentrations at which these mixed colloidal aggregates
form, i.e., the mixed critical microaggregate concentration (CAC*), the mixed critical vesicle concentration
(CVC*), and the mixed critical micelle concentration (CMC*), have been determined from conductivity
data, while the ζ-potential experiments allow for the characterization of the aggregate/solution interface.
The shape and size of the microaggregates and vesicles have been evaluated from TEM and cryo-TEM
micrographs, respectively. All of the experimental evidence has been also analyzed in terms of the theoretical
packing parameter, P.