) Nanoscale Control Over Interfacial Properties in Mixed Reverse Micelles Formulated Using Sodium 1,4-bis-2-ethylhexylsulfosuccinate and Tri-n-octyl Phosphine Oxide Surfactants

E ODELLA; FALCONE R.D.; J J SILBER; CORREA N.M.

Chemphyschem

WILEY-V C H VERLAG GMBH

Lugar: Weinheim; Año: 2016 p. 2407 - 2414

1439-4235

The interfacialproperties of pure reverse micelles (RMs) are a consequenceof the magnitude and nature of noncovalent interactionsbetween confined water and the surfactant polar head.Addition of a second surfactant to form mixed RMs is expectedto influence these interactions and thus affect these propertiesat the nanoscale level. Herein, pure and mixed RMs stabilizedby sodium 1,4-bis-2-ethylhexylsulfosuccinate and tri-n-octylphosphine oxide (TOPO) surfactants in n-heptane were formulatedand studied by varying both the water content and theTOPO mole fraction. The microenvironment generated wassensed by following the solvatochromic behavior of the 1-methyl-8-oxyquinolinium betaine probe and 31P NMR spectroscopy.The results reveal unique properties of mixed RMs andwe give experimental evidence that free water can be detectedin the polar core of the mixed RMs at very low water content.We anticipate that these findings will have an impact onthe use of such media as nanoreactors for many types ofchemical reactions, such as enzymatic reactions and nanoparticlesynthesis.