The Use of two Non-toxic Lipophilic Oils to Generate Environmentally Friendly Anionic Reverse Micelles without cosurfactant. Comparison with the behavior found for traditional organic non-polar solvents

V GIRARDI; JUANA J. SILBER; N. MARIANO CORREA; R. DARIO FALCONE

COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2014 vol. 457 p. 354 - 362

0927-7757

tIn this work two different non-toxic solvents/sodium 1,4-bis-2-ethylhexylsulfosuccinate (AOT)/waterreverse micelles (RMs) have been investigated by dynamic (DLS) and static (SLS) light scattering tech-niques. Methyl laurate (ML) and isopropyl myristate (IPM) were used as external non-polar solvents toformulate the AOT RMs without cosurfactant. DLS results reveal the formation of IPM and ML AOT RMscontaining water as a polar component since the droplet sizes values increase as the W0values increase.To the best of our knowledge this is the first report where ML is used to formulate AOT RMs. The dropletssize values, the maximum amount of water solubilized and the aggregation numbers (Nagg, determinedby SLS) of both AOT RMs are dissimilar considering the chemical structure of the external solvents andthey can be explained taking into account the different non-polar solvent penetration to the interface.The results suggest that IPM penetrate more the interface than ML in AOT RMs, diminishing the inter-droplets interactions and producing RMs with smaller sizes and Naggthan ML/AOT. The higher viscosityand polarity of IPM in comparison with ML promotes the interface penetration. Thus, the penetrationof IPM into the interface is higher than ML, making the interface of IPM/AOT RMs more rigid and, inconsequence with smaller droplets sizes values. Finally, a peculiar comparable behavior (droplets size,maximum amount of water solubilized and Nagg) between n-heptane and ML AOT RMs and benzene andIPM AOT RMs was observed. These results present a very promissory field since that the unique propertiesof the alkanes/AOT/water RMs can be obtained using non-toxic lipophilic oils and, in the same way theopportunity to formulate environmentally friendly AOT RMs.