Aggregation phenomena on the ternary ionic-nonionic surfactant system: didodecyldimethylammonium bromide/octyl-beta-D-glucopyranoside/water. Mixed microaggregates, vesicles, and micelles.
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-C(12)DMAB), (ii) a nonionic single-chain surfactant, octyl-beta-D-glucopyranoside (OBG), and (iii) water. The study has been carried out by means of conductivity, zeta-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 zeta-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 zeta-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.
Junquera
Elena
E
Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
del Burgo
Patricia
P
Arranz
Rocío
R
Llorca
Oscar
O
Aicart
Emilio
E
D020285:Cryoelectron Microscopy; D004586:Electrophoresis; D005960:Glucosides / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D008823:Micelles; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
D005960:Glucosides; D007477:Ions; D008823:Micelles; D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; D014867:Water; C046112:didodecyldimethylammonium; C018619:octyl-beta-D-glucoside