Mechanistic Investigations of Growth of Anisotropic Nanostructures in Reverse Micelles

Abstract

Tailoring the characteristics of anisotropic nanostructures like size, morphology, aspect ratio, and size dispersity is of extreme importance due to the unique and tunable properties including catalytic, optical, photocatalytic, magnetic, photochemical, electrochemical, photoelectrochemical, and several other physical properties. The reverse microemulsion (RM) method offers a useful soft-template and low-temperature procedure that, by variation of experimental conditions and nature of reagents, has proved to be extremely versatile in synthesis of nanostructures with tailored properties. Although many reports of synthesis of nanostructures by the RM method exist in the literature, most of the research studies carried out still follow the "hit and trial" method where the synthesis conditions, reagents, and other factors are varied and the resulting characteristics of the obtained nanostructures are justified on the basis of existing physical chemistry principles. Mechanistic investigations are scarce to generate a set of empirical rules that would aid in preplanning the RM-based synthesis of nanostructures with desired characteristics as well as make the process viable on an industrial scale. A consolidation of such research data available in the literature is essential for providing future directions in the field. In this perspective, we analyze the literature reports that have investigated the mechanistic aspects of growth of anisotropic nanostructures using the RM method and distil the essence of the present understanding at the nanoscale timescale using techniques like FCS and ultrafast spectroscopy in addition to routine techniques like DLS, fluorescence, TEM, etc.

Improved Buchwald–Hartwig Amination by the Use of Lipids and Lipid Impurities

“…Fatty acids can react with the base (K 2 CO 3 ), generating corresponding potassium salts, which have improved solubility in fats and can act as shuttle bases or phase transfer catalysts. Amphiphiles can form reversed micelles that have been shown to act as microreactors for Pd-catalyzed transformations . Accordingly, we set a series of control experiments to investigate the effect of various commercially available natural amphiphiles (50 mg) on the reaction in rapeseed oil (2 mL) from Sigma-Aldrich (Chart ).…”

In SituDielectric Spectroscopy Monitoring of Silica Nanoparticle Synthesis in Cationic Water-in-Oil Microemulsions

“…Evolution of Dielectric Relaxations during the Synthesis Processes. The synthesis of silica NPs in reverse MEs has been extensively investigated, 8 and it has been found that a great number of factors can influence the synthesis process, such as water:surfactant molar ratio R, the cosurfactant:surfactant ratio, and the water:TEOS ratio. In addition to these structural factors, many nonstructural factors can affect the synthesis process, as well, for example, synthesis time, 5 reaction products, 7 and interdroplet interaction.…”

“…This situation has encouraged a great number of mechanistic studies of NP synthesis processes alongside the ME-based NP synthesis works. 8,9 Recently, in situ mechanistic studies by means of timeresolved techniques have demonstrated superiority in giving indepth insights into the dynamic nature of NP formation in ME-based synthesis. 10−18 In such studies, the evolution profiles of designated system properties provided by timeresolved techniques can directly mirror the dynamic synthesis processes in real time, through correlations of the designated properties with the structural and compositional features of the synthesis system in one aspect or another.…”

“…As a result, the structural qualities of synthesized NPs often fall out of one’s expectation, or achievement of NPs with a desired structure is often a fairly time- and labor-intensive work, even though the structure of ME droplets has been elaborately tuned. This situation has encouraged a great number of mechanistic studies of NP synthesis processes alongside the ME-based NP synthesis works. , …”

Sustainable Ethanol Production From Sugarcane Molasses by Saccharomyces cerevisiae Immobilized on Chitosan-Coated Manganese Ferrite

“…Various fabrication methods have been reported to prepare spinel manganese ferrite nanocrystals, including the sol-gel method (Banalata et al, 2014), coprecipitation (Irfán et al, 2012), synthesis in reverse micelles (Das et al, 2021) and the hydrothermal method (Mebdir and Sadiyha, 2019). Each method of ferrite obtaining has its advantages and disadvantages.…”