Self-Assembled Polyoxometalates Nanoparticles as Pickering Emulsion Stabilizers

Abstract

We easily produced a series of polyoxometalate (POM) nanoparticles by taking benefit from electrostatic attractions between various POMs and alkylammonium cations. These self-assembled supramolecular nanoparticles are fully characterized in terms of shape, nanostructure, and physicochemical properties. The nanoparticle differences are discussed on the basis of the chemical composition of the initial POM. Moreover, such particles have the ability to stabilize water-in-oil Pickering emulsions. Using a gel-trapping technique coupled to atomic force microscopy (AFM) observations, we determined their affinity toward oil by the contact angle of adsorbed nanoparticles. We show that the emulsion droplet size and stability can be directly linked to the nanoparticle hydrophobicity, which is tuned by the charge localization and molecular packing of POMs with the ammonium cations. Such particles are of special interest as they open large possibilities for Pickering interfacial catalysis.

Get Beyond Limits: From Colloidal Tectonics Concept to the Engineering of Eco-Friendly Catalytic Systems

“…By analogy with the molecular tectonics definition, I propose to use “colloidal tectonics” to define the art and science of supramolecular formation of (supra)colloidal structures using tectonic subunits (molecular building blocks). Consequently, a bottom-up construction of large colloidal systems (until microscale) is allowed from tectons (Leclercq et al, 2015 ). The most important aspect of this method appears to be the fact that the assembling process is based on molecular recognition operating at the level of the complementary tectons providing an infinite variety of reversible (supra)colloidal systems with predictable, versatile and switchable properties.…”

The Ouzo effect to selectively assemble molybdenum clusters into nanomarbles or nanocapsules with increased HER activity

“…21 The elaboration of nanocapsules is more challenging although it provides interesting opportunities resulting from their internal cavity, with potential applications in catalysis, photonics, enzyme protection or drug carriers. 22,23 Generally, inorganic capsules are formed by adsorption of the inorganic material on a solid or molecular template. 11,24 Very recently, we demonstrated that under solvent shifting conditions, small (~ 5 nm) hydrophobic nanoparticles stabilize liquid/liquid interfaces in mixtures of water and THF, forming liquid droplets coated by nanoparticles.…”

Beyond Charge Balance: Counter‐Cations in Polyoxometalate Chemistry

“…The SECs with their bulky shell of long-chain hydrocarbons can be dissolved in organic solvents and these can be transferred to a surface for molecular devices with electrochemical or electrochromic response, catalytic function, [123,126] gas adsorption, [123] or Li + [127] or H + [128] conduction for energy conversion and storage. Organically-soluble SECs have also been proposed for applications including stabilization of emulsions, [129] extraction and separation of uranium [130] and NMR paramagnetic relaxation reagents. [131] In the spirit of this comprehensive Review about POMcounter-cations, we will not go in depth into SEC applications, as this has been recently reviewed.…”