Nanostructured fluids based on propylene carbonate/water mixtures.
The microstructure of aggregates formed by sodium dodecyl sulfate (SDS) and 1-pentanol in mixtures of water and a polar aprotic solvent (propylene carbonate, PC) was investigated by means of pulsed gradient spin-echo NMR, dynamic light scattering, viscosity, and conductivity measurements. PC partitions itself between micelles and aqueous bulk. The fraction of micellized propylene carbonate remains constant along PC-dilution, and the phase separation takes place when the composition of continuous phase attains the PC/water miscibility gap. The micellized PC is present mainly in the micelle's palisade and strongly increases the total interfacial area, thus acting as a cosurfactant. At high PC content, the system is composed by very small aggregates (around 10 A in radius) made by few SDS molecules (10-6) and PC and pentanol. The resulting system can be described as a nanostructured fluid with a huge interfacial area and a small dispersed phase.
Palazzo
Gerardo
G
Consorzio Interuniversitario per lo sviluppo dei Sistemi a Grande Interfase (CSGI), Firenze, Italy. palazzo@chimica.uniba.it
Fiorentino
Daniela
D
Colafemmina
Giuseppe
G
Ceglie
Andrea
A
Carretti
Emiliano
E
Dei
Luigi
L
Baglioni
Piero
P