A New Organized Media: Glycerol:N,N-Dimethylformamide/AOT/n-Heptane Reverse Micelles. A UV-Visible Absorption, Dynamic Light Scattering and 1HNMR Investigation

ANDRES DURANTINI; R. DARIO FALCONE; JUANA J. SILBER; CORREA N.M*

JOURNAL OF PHYSICAL CHEMISTRY B - (Print)

AMER CHEMICAL SOC

Año: 2011 vol. 115 p. 5894 - 5902

1520-6106

In this work we investigate the behavior of the glycerol (GY) ? N,N-dimethylformamide (DMF) mixture in homogeneous and in sodium 1,4-bis (2- ethylhexyl) sulfosuccinate (AOT)/n-heptane reversed micelles (RMs) media. To achieve this goal we have used the solvatochromic behavior of 1-methyl-8-oxyquinolinium betaine (QB) as absorption probe, and, dynamic light scattering (DLS).             QB shows strong preferential solvation when is dissolved in the GY:DMF mixture and, as QB is a good hydrogen bond acceptor molecular probe it is preferentially solvated by the GY-DMF hydrogen-bonded (H-bonded) species.             On the other hand, when the GY: DMF mixture was investigated in AOT RMs, the results show that the mixture is encapsulated in the polar core of the AOT RMs. DLS confirms the formation of the GY:DMF/AOT/n-heptane RMs since an increase in the Ws = ([GY]+[DMF])/[AOT] values cause an increment in the RMs droplets sizes. The solvatochromic behavior of QB, which resides at the AOT RMs interface, shows that QB is mostly solvated by GY molecules especially at low Ws values. Thus, it seems that upon encapsulation inside the polar core of the AOT RMs, the GY-DMF interaction diminishes due to the strong AOT-GY interaction. 1HNMR chemical shifts of GY and DMF measured in the different AOT RMs investigated shows that GY and DMF behave practically as not interacting solvents inside the RMs.