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Micropolarity and Hydrogen‐Bond Donor Ability of Environmentally Friendly Anionic Reverse Micelles Explored by UV/Vis Absorption of a Molecular Probe and FTIR Spectroscopy
Author(s) -
Girardi Valeria R.,
Silber Juana J.,
Falcone Ruben Darío,
Correa N. Mariano
Publication year - 2018
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201701264
Subject(s) - solvatochromism , fourier transform infrared spectroscopy , hydrogen bond , chemistry , molecule , solvent , micelle , sodium dodecylbenzenesulfonate , chemical engineering , photochemistry , analytical chemistry (journal) , organic chemistry , aqueous solution , engineering
In the present work we show how two biocompatible solvents, methyl laurate (ML) and isopropyl myristate (IPM), can be used as a less toxic alternative to replace the nonpolar component in a sodium 1,4‐bis‐2‐ethylhexylsulfosuccinate (AOT) reverse micelles (RMs) formulation. In this sense, the micropolarity and the hydrogen‐bond ability of the interface were monitored through the use of the solvatochromism of a molecular probe (1‐methyl‐8‐oxyquinolinium betaine, QB) and Fourier transform infrared spectroscopy (FTIR). Our results demonstrate that the micropolarity sensed by QB in ML RMs is lower than in IPM RMs. Additionally, the water molecules form stronger H‐bond interactions with the polar head of AOT in ML than in IPM. By FTIR was revealed that more water molecules interact with the interface in ML/AOT RMs. On the other hand, for AOT RMs generated in IPM, the weaker water–surfactant interaction allows the water molecules to establish hydrogen bonds with each other trending to bulk water more easily than in ML RMs, a consequence of the dissimilar penetration of nonpolar solvents into the interfacial region. The penetration process is strongly controlled by the polarity and viscosity of the external solvents. All of these results allow us to characterize these biocompatible systems, providing information about interfacial properties and how they can be altered by changing the external solvent. The ability of the nontoxic solvent to penetrate or not into the AOT interface produces a new interface with attractive properties.