Nanoparticles in ionic liquids: interactions and organization

Abstract

Ionic liquids (ILs), defined as low-melting organic salts, are a novel class of compounds with unique properties and a combinatorially great chemical diversity. Ionic liquids are utilized as synthesis and dispersion media for nanoparticles as well as for surface functionalization. Ionic liquid and nanoparticle hybrid systems are governed by a combined effect of several intermolecular interactions between their constituents. For each interaction, including van der Waals, electrostatic, structural, solvophobic, steric, and hydrogen bonding, the characterization and quantitative calculation methods together with factors affecting these interactions are reviewed here. Various self-organized structures based on nanoparticles in ionic liquids are generated as a result of a balance of these intermolecular interactions. These structures, including colloidal glasses and gels, lyotropic liquid crystals, nanoparticle-stabilized ionic liquid-containing emulsions, ionic liquid surface-functionalized nanoparticles, and nanoscale ionic materials, possess properties of both ionic liquids and nanoparticles, which render them useful as novel materials especially in electrochemical and catalysis applications. This review of the interactions within nanoparticle dispersions in ionic liquids and of the structure of nanoparticle and ionic liquid hybrids provides guidance on the rational design of novel ionic liquid-based materials, enabling applications in broad areas.

Creation of energetic biothermite inks using ferritin liquid protein

“…This dispersion mechanism is supported by the observation of a supramolecularly layered shell of ferritin coating the nAl surface (Fig. 1c) by TEM of reconstituted nAl@ferritin IL in water and is consistent with the dispersion mechanism of negatively charged SiO 2 particles in a pure organic ionic liquid34. In this capacity, the cationized ferritin coating on nAl prevented aggregation in the concentrated ferritin ionic liquid through steric and repulsive forces, promoted dispersion, and enabled high mass fractions.…”

“…In the case of nAl in water, nAl was rapidly oxidized to Al(OH) 3 after 2 days at room temperature19. Alternatively, simple imidazolium-based ionic liquids are well known for their exceptional solvent properties and ability to form stable nanoparticle suspensions34. As a result, we examined the dispersion of nAl in 1-butyl-3-methyl-imidazolium chloride ([BMIM]Cl) in order to benchmark the nAl@ferritin protein ionic liquid.…”

Preparation of Ag@mSiO 2 and Pt@mSiO 2 nano composites using trioctylmethyl ammonium hydrogen phthalate (TOMAHP) ionic liquid as reaction medium

“…The DLVO theory has limitation since it consider the ideal case only. According to DLVO theory, the nano particles are not effectively stabilized by only electrostatic repulsion due to the high ionic strength of IL [62,63]. Thus, the extra stabilization energy/force may arise from steric hindrance due to presence of bulky groups (anion, cation), solvation forces due to H-bonding, high viscosity and layer structure of IL.…”

Ionic liquid attached to colloidal silica nanoparticles: as high performance catalyst for the preparation of dihydrofurans under microwave irradiation

“…In recent years, synthesis and immobilization of nanoparticles in ionic liquids (ILs) have been widely studied [16][17][18][19][20][21][22]. Ionic liquids can be considered as valuable key precursor compounds for catalysts [23][24][25][26][27][28][29].…”