0000000001107609
AUTHOR
Domenico Lombardo
Structure and dynamics of dibutylphosphate/n-propylamine ionic liquid: A multi-scale theoretical study
Abstract Owing to the amphiphilic nature of their constituent molecules, binary mixtures of pure liquid surfactants are usually characterized by enhanced nano-segregation and thus can exhibit interesting transport properties and complex macroscopic behavior. In this ambit it was recently shown by Turco Liveri et al. (2018) that mixtures of short aliphatic chains compounds at room temperature, such as dibutyl phosphate (DBP) and n-propylamine (PA) liquids, display ionic liquid–like behavior ascribed to phosphate-to-amine proton transfer. To gain a detailed molecular picture of the system structure and dynamics and to understand the molecular mechanisms at the basis of the observed behavior, …
Molecular association of small amphiphiles: Origin of ionic liquid properties in dibutyl phosphate/propylamine binary mixtures
Abstract Binary mixtures of liquid surfactants, owing to the amphiphilic nature of the molecules involved, can exhibit nano-segregation and peculiar transport properties. The amphiphilicity, and consequently the resulting self-assembly, can be tuned by changing the length of the alkyl chains and the nature of the polar head group. So, in the present study, the structural and dynamic properties of dibutyl phosphate/propylamine liquid mixtures at various compositions have been investigated by Wide Angle X-ray Scattering (WAXS), FT-IR, rheometry and dielectric spectroscopy in order to study the intermolecular association taking place when alkylphosphates and alkylamines with a small apolar par…
Coupling chemical reaction to electrospray: a novel preparation of gold nanostructures
The simultaneous reduction of Au(III) to Au(0), synthesis of gold nanoparticles and their deposition onto boron-doped silicon target have been attained by the electrospray technique. In this way the overall process can be considered as a novel chemical/physical hybrid method which synergically exploits the merits of both approaches. Various experimental conditions have been explored to optimize the process: it has been found that, by applying a negative high voltage to the boron-doped silicon target and with the presence of the surfactant Bis(2-ethylhexyl)sulfosuccinate sodium salt in the solution, a quantitative transformation of Au(III) to Au(0) nanoparticles has been obtained. The deposi…
Synthesis of Yb nanoparticles by laser ablation of ytterbium target in sodium bis(2-ethylhexyl)sulfosuccinate reverse micellar solution
Abstract Surfactant-coated ytterbium nanoparticles were produced by Nd:YAG laser ablation of a Yb bulk target immersed in sodium bis(2-ethylhexyl)sulfosuccinate (AOT)/ n -heptane micellar solution. In our experimental conditions, as highlighted by IR spectroscopy, AOT molecules are not decomposed by the intense laser pulses but play a pivotal role in the stabilisation of Yb nanoparticles. The formation of Yb nanoparticles in the liquid phase was monitored by UV–Vis spectroscopy whereas the Yb/AOT composites obtained by evaporation of the organic solvent were characterised by XPS and TEM. Data analysis consistently shows the presence of surfactant-coated, nearly spherical and non-interacting…
Non-ideal mixing behavior in dibutyl phosphate-propylamine binary liquids: Dielectric and nuclear magnetic resonance investigations
Abstract Owing to the amphiphilic nature of their constituent molecules, binary mixtures of pure liquid surfactants are usually characterized by enhanced nano-segregation and thus can exhibit interesting transport properties and complex macroscopic behavior. In this ambit it was recently shown by Turco Liveri et al. (J. Mol. Liq. 263 (2018) 274–281) at room temperature that mixtures of short aliphatic chains compounds, such as dibutyl phosphate (DBP) and n-propylamine (PA) liquids, due to their ability to allow for phosphate-to-amine proton transfer, display ionic liquid–like behavior with composition-dependent enhanced conductivity, viscosity, and magnetically-induced birefringence. To und…
Anti-Arrhenian behaviour of conductivity in octanoic acid–bis(2-ethylhexyl)amine systems: a physico-chemical study
Pure surfactant liquids and their binary mixtures, owing to the amphiphilic nature of the molecules involved, can exhibit nano-segregation and peculiar transport properties. The structural and dynamic properties of octanoic acid (OA)–bis(2-ethylhexyl)amine (BEEA) liquid mixtures at various compositions have been studied by Wide Angle X-ray Scattering (WAXS), 1H-NMR and broadband dielectric spectroscopy as a function of temperature. It was found that the self-assembly occurs via proton exchange between the OA COOH group and the BEEA NH one; such self-assembled local structures are affected anisotropically by a temperature increase so that the thermal dilatation is more marked in a direction …
How self-assembly of amphiphilic molecules can generate complexity in the nanoscale
Abstract Given the importance of nanomaterials and nanostructures in modern technology, in the past decades much effort has been directed to set up efficient bottom up protocols for the piloted self-assembly of molecules. However, molecules are generally disinclined to adopt the desired structural organization because they behave according to their own specific intermolecular interactions. Thus, only some selected classes of chemical compounds are capable to lead to useful self-assembled structures. Amphiphiles, simultaneously possessing polar and apolar moieties within their molecular architecture, can give a wide scenario of possible intermolecular interactions: polar–polar, polar–apolar,…
Spectroscopic and structural characterization of pure and FeCl3-containing tri-n-butyl phosphate
The spectroscopic properties and liquid structure of pure tri-n-butyl phosphate (TBP) and FeCl3/TBP solutions have been investigated by Uv–Vis and Raman spectroscopies, X-ray diffraction and conductometry. Uv–Vis and Raman spectra, supported by conductometric measurements, consistently indicate that the solubilized salt is present mostly as TBP n [FeCl3 − n ] n+ and FeCl4 − complex ions due to specific interaction with the TBP phosphate group. Thanks to this interaction, a high amount of salt (up to 13 % w/w) can be dissolved despite the relatively low dielectric constant of TBP. The X-ray diffractogram of pure TBP has been interpreted in terms of three main contributions which can be attri…
Iron and lithium-iron alkyl phosphates as nanostructured material for rechargeable batteries
Abstract Inorganic/organic hybrid materials composed by iron atoms bonded to an alkyl phosphate can be easily synthesized by mixing at 110 °C iron chlorides with tri-alkyl phosphates. Since structural information on these products are lacking and taking into account that lithium/iron organic hybrid materials are important in lithium ion battery technology we report here the physico-chemical characterization of different hybrid lithium/iron butylphosphates. These materials are characterized by the presence of elongated hexagonal crystals stable up to 315 °C. The insertion of lithium does not affect the local structure. Thanks to such structures the material can be electrochemically-cycled an…
Structural and optical properties of novel surfactant-coated Yb-TiO2 nanoparticle
Abstract In this paper a novel hybrid approach to synthesise composite nanoparticles is presented. It is based on the laser ablation of a bulk target (Yb) immersed in a reversed micellar solution which contains nanoparticles of a different host material (TiO2 nanoparticles) previously synthesised by chemical method. This approach thus exploits the advantages of the chemical synthesis through reversed micellar solution (size control, nanoparticle stabilisation), and of the laser ablation (‘‘clean’’ synthesis, no side reactions). Central role is played by the microscopic processes controlling the deposition of the ablated Yb atoms onto the surface of TiO2 nanoparticles which actually behave a…