Micropolarity and Hydrogen‐Bond Donor Ability of Environmentally Friendly Anionic Reverse Micelles Explored by UV/Vis Absorption of a Molecular Probe and FTIR Spectroscopy

Abstract

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.

Biocompatible Solvents and Ionic Liquid-Based Surfactants as Sustainable Components to Formulate Environmentally Friendly Organized Systems

“…This could be an alternative when a classical toxic solvent needs to be replaced by a non-toxic solvent for biological applications. More recently, the micropolarity and the hydrogen-bond ability of the interface of these RMs, ML/Na-AOT/water, and IPM/Na-AOT/water were monitored through the use of the solvatochromism of a molecular probe (1-methyl-8-oxyquinolinium betaine, QB) and Fourier transform infrared spectroscopy (FT-IR) [ 111 ]. The studies confirmed that due to the dissimilar penetration of these oils into the interfacial region, the micropolarity and the encapsulated water structure were different.…”

Free H‐Bonding Interaction Sites in Rigid‐Chain Polymers and Their Filling Approach: A Molecular Dynamics Simulation Study

“…In fact, it is difficult to investigate the properties of intermolecular H‐bonds clearly, such as proportion of free sites, H‐bonding length, and strength due to the limitations of traditional characterization such as FT‐IR, Raman spectrum, and NMR. [ 12 ] Molecular Dynamics (MD) simulation is proven an effective tool with a provision of atomic‐scale information and has become a powerful simulation technique. Numerous researchers have studied different polymers at multilevel scales by MD simulation, [ 13 ] including the behavior and properties of polymer chains at the molecular level, the aggregation structure at large scale, and the macroscopic physical properties.…”

Characterization of Anionic Reverse Micelles Formulated on Biobased Solvents as Replacing Conventional Nonpolar Organic Solvents

“…The formation of the corresponding AOT RMs and some properties of these system such as W 0 , droplets size values, CMC, and N agg , among others, depending strongly on the chemical structure of the external solvent. 3,4,7 However, the search for new nonpolar and nontoxic solvents for the elaboration of more RMs still remains of interest. In this context, solvents derived from biomass, named as biobased solvents, could be a good alternative for this purpose.…”

“…Reversed micelles (RMs) are organized systems of nanometric size formed by three components, i.e., a polar solvent (generally water), a surfactant, and some nonpolar solvent which form a thermodynamically stable and optically transparent solution . Due to the diverse applications of RMs, , in the past decade there has been much interest in assessing the nature of the surfactants and of nonpolar solvents that can be part of these organized systems. − One of the surfactants more often used to form RMs is the anionic sodium 1,4-bis-2-ethylhexylsulfosuccinate (AOT, Scheme ). Diverse RMs using AOT and different organic nonpolar solvents, aromatic and aliphatic, have been reported .…”

“…Nevertheless, replacing these toxic and volatile petroleum-based solvents (used as nonpolar solvents in RMs) by more environmentally friendly alternatives is a challenge to generate RMs more biocompatible and with less impact on the environment. , Given the above, recently two nontoxic lipophilic oils such as methyl laurate (ML) and isopropyl myristate (IPM) have been used to formulate different environmentally friendly RMs. The formation of the corresponding AOT RMs and some properties of these system such as W 0 , droplets size values, CMC, and N agg , among others, depending strongly on the chemical structure of the external solvent. ,, However, the search for new nonpolar and nontoxic solvents for the elaboration of more RMs still remains of interest. In this context, solvents derived from biomass, named as biobased solvents, could be a good alternative for this purpose.…”