Nanoarchitected graphene/copper oxide nanoparticles/MoS ternary thin films as highly efficient electrodes for aqueous sodium-ion batteries.

Sodium-ion batteries (SIBs) operating in aqueous electrolyte are an emerging technology that promises to be safer, cheaper, more sustainable and more efficient than their lithium-based counterparts. One of the great challenges associated with this technology is the development of advanced materials with high specific capacity to be used as electrodes. Herein, we describe an ingenious strategy to prepare unprecedented tri-component nanoarchitected thin films with superior performance when applied as anodes in aqueous SIBs.

New highly antigenic linear B cell epitope peptides from PvAMA-1 as potential vaccine candidates.

Peptide-based vaccines have demonstrated to be an important way to induce long-lived immune responses and, therefore, a promising strategy in the rational of vaccine development. As to malaria, among the classic vaccine targets, the Apical membrane antigen (AMA-1) was proven to have important B cell epitopes that can induce specific immune response and, hence, became key players for a vaccine approach. The peptides selection was carried out using a bioinformatic approach based on Hidden Markov Models profiles of known antigens and propensity scale methods based on hydrophilicity and secondary structure prediction.

Facile room temperature synthesis of large graphene sheets from simple molecules.

The largest graphene sample obtained through a chemical reaction under ambient conditions (temperature and pressure), using simple molecules such as benzene or -hexane as precursors, is reported. Starting from a heterogeneous reaction between solid iron chloride and the molecular precursor (benzene and -hexane) at a water/oil interface, graphene sheets with micrometric lateral size are obtained as a film deposited at the liquid/liquid (L/L) interface. The pathway involving the cyclization and aromatization of -hexane to benzene at the L/L interface, and the sequence of conversion of benzene to biphenyl and biphenyl to condensed rings (which originates the graphene structures) was followed by different characterization techniques and a mechanistic proposal is presented.

Direct and one-step synthesis of polythiophene/gold nanoparticles thin films through liquid/liquid interfacial polymerization.

This work demonstrates a simple and one-step synthesis of polythiophene/gold nanoparticles (PT/Au) nanocomposite thin films, through a liquid-liquid (L/L) interfacial polymerization route. Starting from an aqueous solution of tetrachloroauric acid (acting both as metallic gold source and oxidizing agent to start the oxidative polymerization of thiophene), and a solution of thiophene in n-hexane, a biphasic L/L system was originated. In the following, the interface acted as a meeting-point for the reactants, and the polymerization reaction took place, leading to self-assembled PT/Au film between the two immiscible liquids.

Matching long-period grating modes and localized plasmon resonances: effect on the sensitivity of the grating to the surrounding refractive index.

The sensitivity and dynamical range of an optical-fiber transducer consisting of a long-period grating coated with gold nanoparticles is investigated. For a grating with an 80 μm spatial periodicity, the resonances close to the turning point lie within the 450-900 nm spectral range. Employing a bottom-up production route, the localized surface plasmon resonance of gold nanoparticles is matched to the grating resonances; it is shown that this results in an increase in the refractive index sensitivity of the device.

One material, multiple functions: graphene/Ni(OH) thin films applied in batteries, electrochromism and sensors.

Different nanocomposites between reduced graphene oxide (rGO) and Ni(OH) nanoparticles were synthesized through modifications in the polyol method (starting from graphene oxide (GO) dispersion in ethylene glycol and nickel acetate), processed as thin films through the liquid-liquid interfacial route, homogeneously deposited over transparent electrodes and spectroscopically, microscopically and electrochemically characterized. The thin and transparent nanocomposite films (112 to 513 nm thickness, 62.6 to 19.

Nickel nanoparticles with hcp structure: Preparation, deposition as thin films and application as electrochemical sensor.

Hexagonal close packed (hcp) nickel nanoparticles stabilized by polyvinylpyrrolidone (PVP) were synthesized through the thermal treatment of face centered cubic (fcc) nickel nanoparticles. Controlling both the temperature of the heat treatment and the amount of PVP was possible the control of the hcp/fcc rate in the samples, where the higher Ni/PVP ratio produces only the hcp-nickel phase (average size of 8.9 nm) highly stable in air.

The total chemical synthesis of polymer/graphene nanocomposite films.

A versatile and room temperature synthesis of thin films of polymer/graphene is reported. Drastically differing from other methods, not only the polymer but also the graphene are completely built from their simplest monomers (thiophene and benzene) in a one-pot polymerization reaction at a liquid-liquid interface. The materials were characterized and electronic properties are presented.

Plasmonic optical fiber sensors: enhanced sensitivity in water-based environments.

In this work, we demonstrate a refractometric fiber sensor with improved sensitivity for refractive indices ranging from 1.3629 to 1.4479.

Thin and transparent films of graphene/silver nanoparticles obtained at liquid-liquid interfaces: preparation, characterization and application as SERS substrates.

We report here the synthesis and characterization of transparent and homogeneous thin films of reduced graphene oxide/silver nanoparticles (rGO/AgNPs) nanocomposites, starting from graphene oxide (GO) or reduced graphene oxide (rGO), directly obtained at a water/toluene liquid-liquid interface. Different films (obtained by varying the Ag/rGO or Ag/GO ratio) were prepared, deposited over glass or plastic substrates, and characterized by X-ray diffraction, UV-Vis and Raman spectroscopy, thermal analysis, transmission and scanning electron microscopy. Samples were evaluated as substrates for surface-enhanced Raman spectroscopy (SERS), using dilute solutions (1×10(-7) mol L(-1)) of a common probe molecule, 4-aminothiophenol (4-ATP).

Transparent and conductive thin films of graphene/polyaniline nanocomposites prepared through interfacial polymerization.

This communication reports a simple, one-pot procedure for the synthesis and processing of transparent and conductive thin films of graphene/polyaniline nanocomposites based on an interfacial polymerization. Thin films presenting transmittance of 89% and sheet resistance of 60.6 Ω sq(-1) are spontaneously obtained and can be easily transferred to suitable substrates.

V2O5 nanoparticles obtained from a synthetic bariandite-like vanadium oxide: synthesis, characterization and electrochemical behavior in an ionic liquid.

Highly stable and crystalline V(2)O(5) nanoparticles with an average diameter of 15 nm have been easily prepared by thermal treatment of a bariandite-like vanadium oxide, V(10)O(24) x 9 H(2)O. Their characterization was carried out by powder X-ray diffractometry (XRD), Fourier transform infrared (FT-IR) and Raman spectroscopies, and transmission electron microscopy (TEM). The fibrous and nanostructured film obtained by electrophoretic deposition of the V(2)O(5) nanoparticles showed good electroactivity when submitted to cyclic voltammetry in an ionic liquid-based electrolyte.

A simple two-phase route to silver nanoparticles/polyaniline structures.

Novel silver nanoparticles/polyaniline composites were obtained through a two-phase water/toluene interfacial reaction. We show that by rigorously controlling the reaction time, different structures of the nanocomposites can be obtained, such as a thin sheet of polyaniline around the silver nanoparticles or a polymer mass with nanoparticles homogeneously embedded within it. Samples were characterized by FT-IR, UV-vis-NIR and Raman spectroscopy, X-ray diffraction, cyclic voltammetry, TEM, and HRTEM.

Sol-gel processing of a bimetallic alkoxide precursor confined in a porous glass matrix: a route to novel glass/metal oxide nanocomposites.

In this work we present the utilization of the heterometallic alkoxide [FeCl{Ti(2)(OPr(i))(9)}] as the first sol-gel single-source precursor to achieve nanocomposites made of iron and titanium oxides incorporated into Porous Vycor Glass (PVG). The nanocomposites were prepared by the impregnation of the precursor in a PVG plate followed by hydrolysis reactions. Different samples were obtained by further thermal treatment of the hydrolyzed sample.

Influence of synthetic parameters on the size, structure, and stability of dodecanethiol-stabilized silver nanoparticles.

Metal nanoparticles (NP) are very attractive because of their size- and shape-dependent properties. A widely used preparation of ligand-stabilized metal NP is the two-phase liquid-liquid method using dodecanethiol (DT) as ligand. This work presents various procedures to synthesize dodecanethiol-capped silver NPs, all of them based on a two-phase liquid-liquid method.