Search results for " Coating."
showing 10 items of 2558 documents
Increasing the nuclearity and spin ground state in a new family of ferromagnetically-coupled {Ni10} disk-like complexes bearing exclusively end-on br…
2018
The synthesis of a new family of ferromagnetically-coupled {Ni10} clusters counterbalanced by various [Ln(NO3)5]2− ions is herein described. The resulting compounds are organic chelate-free and the metal ions are exclusively bridged by end-on azido ligands to stabilize a beautiful disk-like topology reminiscent of the structure of the brucite mineral.
Photoluminescence quantum yield exceeding 80% in low dimensional perovskite thin-films via passivation control
2017
Quasi-2D perovskites with the BA : MA molar ratio equal to 3 : 3 show a remarkable PLQY exceeding 80%, thanks to the use of an electron donor as the passivating agent. These films have been applied in LEDs that exhibit high brightness exceeding 1000 cd m−2 and current efficiencies >3 cd A−1.
Formation of an unprecedented (CuBr)5 cluster and a zeolite-type 2D-coordination polymer: a surprising halide effect
2013
A unique pentanuclear cluster within a zeolite-type polymer ([Cu5(μ4-Br)(μ3-Br)2(μ2-Br)2](μ2-MeSPr)3)n (1; void space >81%) and a luminescent 1D ([Cu(μ3-I)]4(MeSPr)3)n polymer, 2, are formed when MeSPr reacts with CuBr and CuI.
Where Is the Most Hydrophobic Region? Benzopurpurine Self-Assembly at the Calcite–Water Interface
2017
Control of molecular self-assembly at solid–liquid interfaces is challenging due to the complex interplay between molecule–molecule, molecule–surface, molecule–solvent, surface–solvent, and solvent–solvent interactions. Here, we use in-situ dynamic atomic force microscopy to study the self-assembly of Benzopurpurine 4B into oblong islands with a highly ordered inner structure yet incommensurate with the underlying calcite (10.4) surface. Molecular dynamics and free energy calculations provide insights by showing that Benzopurpurine 4B molecules do not anchor to the surface directly but instead assemble on top of the second hydration layer. This seemingly peculiar behavior was then rationali…
Reactivity of gypsum faces according to the relative humidity by scanning force microscopy
1997
Abstract This article reports the experimental observation of the stability of the different faces of calcium sulphate dihydrate (gypsum CaSO 4 .2H 2 O) according to the relative humidity. Scanning Force Microscopy experiments were carried out with a view to discerning the topography of the surfaces, the chemical compositional domains, and in an attempt to evaluate the friction and viscoelastic properties of the surface. Our results indicate that the (010) face of gypsum is hydrophilic and very reactive contrary to the less hydrophilic (120) and (101) faces which remain stable depending on the relative humidity. It is clear from our results that a precipitation like process can be induced b…
Deposition order controls the first stages of a metal-organic coordination network on an insulator surface
2016
| openaire: EC/FP7/610446/EU//PAMS We report on first stages toward the formation of a surface-confined metal-organic coordination network (MOCN) by sequential deposition of biphenyl-4,4′-dicarboxylic acid and iron atoms on the surface of a bulk insulator, calcite (10.4). The influence of the deposition order on the structure formation is studied by noncontact atomic force microscopy operated in ultrahigh vacuum at room temperature. It is found that sequential deposition facilitates MOCN formation when the organic linker molecules are first adsorbed on the surface, followed by iron deposition. This observation is explained by first-principles computations, indicating that the metal-molecule…
Rheological and Mechanical Behavior of LDPE/Calcium Carbonate Nanocomposites and Microcomposites
2012
The increase of the interest in polymer nanocomposites has been leading to continuous growing search toward nanofillers alternative to the widely known clay-based ones. One of these possible alternatives is represented by calcium carbonate nanoparticles, which have not been widely investigated in such context. In this article, a study on the rheological and morphological behavior of dif- ferent low density polyethylene-calcium carbonate nanocomposites, compared with a reference calcium carbonate microcomposite, is presented. Several different nanosized calcium carbonates at different amounts were used. The results from the rheological and me- chanical tests outlined that only minor changes …
Stable amorphous calcium oxalate: synthesis and potential intermediate in biomineralization.
2014
Amorphous calcium oxalate nanoparticles with sizes of 10–30 nm were synthesized at room temperature by the hydrolysis of a dimethyl oxalate from ethanol solution.
Reversible Tuning of Ca Nanoparticles Embedded in a Superionic CaF2 Matrix
2019
Controlling the size and shape of metallic colloids is crucial for a number of nanotechnological applications ranging from medical diagnosis to electronics. Yet, achieving tunability of morphological changes at the nanoscale is technically difficult and the structural modifications made on nanoparticles generally are irreversible. Here, we present a simple nonchemical method for controlling the size of metallic colloids in a reversible manner. Our strategy consists of applying hydrostatic pressure on a Ca cationic sublattice embedded in the irradiated matrix of CaF2 containing a large concentration of defects. Application of our method to CaF2 along with in situ optical absorption of the Ca…
Solvation of a probe molecule by fluid supercooled water in a hydrogel at 200 K
2008
By combining electron paramagnetic resonance (EPR) measurements on a nitroxide probe and differential scanning calorimetry (DSC), we demonstrate existence of liquid supercooled water in a silica hydrogel with high hydration level down to temperatures of at least 198 K. Besides the major fraction of liquid supercooled water, a minor fraction crystallizes at about 236 K during cooling and melts at 246 K during heating. The liquid domains are of sufficient size to solvate the nearly spherical paramagnetic probe molecule TEMPO with a diameter of about 6 angstrom. Analysis of EPR spectra provides the rotational correlation time of the probe that is further used to compare the viscosity of the su…