Nanocomposite Polymer Electrolytes of Sodium Alginate and Montmorillonite Clay

Nanocomposite polymer electrolytes (NPEs) were synthesized using sodium alginate (Alg) and either sodium (SCa-3-Na⁺)- or lithium (SCa-3-Li⁺)-modified montmorillonite clays. The samples were characterized by structural, optical, and electrical properties. SCa-3-Na⁺ and SCa-3-Li⁺ clays’ X-ray structural analyses revealed peaks at 2θ = 7.2° and 6.7° that corresponded to the interlamellar distances of 12.3 and 12.8 Å, respectively. Alg-based NPEs X-ray diffractograms showed exfoliated structures for samples with low clay percentages. The increase of clay content promoted the formation of intercalated structures. Electrochemical Impedance Spectroscopy revealed that Alg-based NPEs with 5 wt% of SCa-3-Na⁺ clay presented the highest conductivity of 1.96 × 10⁻² S/cm², and Alg with 10 wt% of SCa-3-Li⁺ showed conductivity of 1.30 × 10⁻² S/cm², both measured at 70 °C. From UV-Vis spectroscopy, it was possible to infer that increasing concentration of clay promoted a decrease of the samples’ transmittance and, consequently, an increase of their reflectance.     

Fano blockade by a bose-einstein condensate in an optical lattice

We study the transport of atoms across a localized Bose-Einstein condensate in a one-dimensional optical lattice. For atoms scattering off the condensate, we predict total reflection as well as full transmission for certain parameter values on the basis of an exactly solvable model. The findings of analytical and numerical calculations are interpreted by a tunable Fano-like resonance and may lead to interesting applications for blocking and filtering atom beams.     

Acid–base sensor based on sol–gel encapsulation of bromothymol blue in silica: application for milk spoilage detection

Journal of Sol-Gel Science and Technology - In this work, silica capsules containing bromothymol blue (BTB) were synthesized by a modified Stöber sol–gel method. These silica capsules...     

Electrochemical Determination of Organic Compounds in Automotive Fuels

This article critically reviews the electroanalytical methods devoted for the determination of organic compounds in automotive fuels that can range from contaminants to additives typically introduced into liquid biofuels and liquid fossil fuels. Contaminants such as aldehydes and ketones in bioethanol, free fatty acids and glycerol in biodiesel, and sulfur and nitrogen organic compounds in gasoline and diesel fuel, and additives such as colour markers and antioxidants added to fuels were determined by electroanalytical methods. Special focus is given to electrodes, electrochemical techniques, and sample preparation strategies. Future directions of research on electroanalysis of liquid fuels are presented.     

Development of a Simple and Fast Electrochemical Method for Screening and Stoichiometric Determination of Dimenhydrinate

Dimenhydrinate (DIM) is a salt composed by the combination of two active pharmaceutical ingredients: diphenhydramine (DIP) and 8‐chlorotheophylline (CTP). In this work, the use of batch injection analysis with multiple pulse amperometric detection (BIA‐MPA) was proposed for the first time for fast stoichiometric determination of DIM. DIP (cation) and CTP (anion) were determined simultaneously in pharmaceutical samples with a simple and fast injection procedure (70 injections h^?1). Additional strategies were also proposed for rapid screening of samples containing the DIM salt. By a simple injection of a sample into the BIA system (without using of calibration curve), reliable information about stoichiometry of the DIM salt (1 : 1; DIP:CTP) and presence or absence of interfering species (electroactive) can be achieved.     

Electronic and Structural Properties of Highly Aluminum Ion Doped TiO2 Nanoparticles: A Combined Experimental and Theoretical Study

This study presents the experimental and theoretical study of highly internally Al‐doped TiO₂ nanoparticles. Two synthesis methods were used and detailed characterization was performed. There were differences in the doping and the crystallinity, but the nanoparticles synthesized with the different methods share common features. Anatase to rutile transformation occurred at higher temperatures with Al doping. X‐ray photoelectron spectroscopy showed the generation of oxygen vacancies, which is an interesting feature in photocatalysis. In turn, the band‐gap energy and the valence band did not change appreciably. Periodic density functional calculations were performed to model the experimentally doped structures, the formation of the oxygen vacancies, and the band gap. Calculation of the density of states confirmed the experimental band‐gap energies. The theoretical results confirmed the presence of Ti⁴⁺ and Al³⁺. The charge density study and electron localization function analysis indicated that the inclusion of Al in the anatase structure resulted in a strengthening of the Ti?O bonds around the vacancy.     

Impact of Positional Isomerism on Pathway Complexity in Aqueous Media

Pathway complexity has become an important topic in recent years due to its relevance in the optimization of molecular assembly processes, which typically require precise sample preparation protocols. Alternatively, competing aggregation pathways can be controlled by molecular design, which primarily rely on geometrical changes of the building blocks. However, understanding how to control pathway complexity by molecular design remains elusive and new approaches are needed. Herein, we exploit positional isomerism as a new molecular design strategy for pathway control in aqueous self‐assembly. We compare the self‐assembly of two carboxyl‐functionalized amphiphilic BODIPY dyes that solely differ in the relative position of functional groups. Placement of the carboxyl group at the 2‐position enables efficient pairwise H‐bonding interactions into a single thermodynamic species, whereas meso‐substitution induces pathway complexity due to competing hydrophobic and hydrogen bonding interactions. Our results show the importance of positional engineering for pathway control in aqueous self‐assembly.     

Dual Amperometric Immunosensor for Improving Cancer Metastasis Detection by the Simultaneous Determination of Extracellular and Soluble Circulating Fraction of Emerging Metastatic Biomarkers

This paper reports the development of a dual immunosensor using magnetic microcarriers (MBs) and amperometric transduction at dual screen‐printed carbon electrodes (SPdCEs) for the simultaneous determination of two biomarkers: interleukin‐13 receptor α2 (IL‐13Rα2) and E‐cadherin (E‐CDH), with both extracellular and soluble fraction; oncogenic and tumor suppressor markers, respectively, of great relevance in metastatic processes. The implemented methodology involved the formation of sandwich‐type immunocomplexes using specific capture antibodies immobilized onto carboxylic acid magnetic microbeads (HOOC‐MBs), and biotinylated detector antibodies labeled with streptavidin?horseradish peroxidase conjugates (Strep‐HRP). The amperometric detection was performed by addition of hydrogen peroxide in the presence of hydroquinone (HQ) as the redox mediator. The dual immunosensing platform provided linear calibration ranges suitable for the determination of both biomarkers in liquid and solid clinical specimens as well as excellent selectivity against other cancer biomarkers. This simple handling dual bioplatform was applied to the determination of the soluble and extracellular fraction of the target biomarkers in serum and paraffined‐embedded tissues from colorectal cancer (CRC) patients diagnosed at different tumor grade. The obtained results reveal great potential of this configuration to improve the reliability in diagnosing metastatic CRC.     

A Low‐Temperature Molecular Precursor Approach to Copper‐Based Nano‐Sized Digenite Mineral for Efficient Electrocatalytic Oxygen Evolution Reaction

In the urge of designing noble metal‐free and sustainable electrocatalysts for oxygen evolution reaction (OER), herein, a mineral Digenite Cu₉S₅ has been prepared from a molecular copper(I) precursor, [{(PyHS)₂Cu^I(PyHS)}₂](OTf)₂ ( 1 ), and utilized as an anode material in electrocatalytic OER for the first time. A hot injection of 1 yielded a pure phase and highly crystalline Cu₉S₅, which was then electrophoretically deposited (EPD) on a highly conducting nickel foam (NF) substrate. When assessed as an electrode for OER, the Cu₉S₅/NF displayed an overpotential of merely 298±3 mV at a current density of 10 mA cm^?2 in alkaline media. The overpotential recorded here supersedes the value obtained for the best reported Cu‐based as well as the benchmark precious‐metal‐based RuO₂ and IrO₂ electrocatalysts. In addition, the choronoamperometric OER indicated the superior stability of Cu₉S₅/NF, rendering its suitability as the sustainable anode material for practical feasibility. The excellent catalytic activity of Cu₉S₅ can be attributed to the formation of a crystalline CuO overlayer on the conductive Cu₉S₅ that behaves as active species to facilitate OER. This study delivers a distinct molecular precursor approach to produce highly active copper‐based catalysts that could be used as an efficient and durable OER electro(pre)catalysts relying on non‐precious metals.     

Self-assembling and phase coexistence of SW trimers as complex amphiphile analogues. I. Simulations

We analyse by discrete molecular dynamics the self-assembly of SW trimer particles that contain a different number of attractive and repulsive spheres. They also have different geometries: linear, obtuse, rectangular and equilateral. We identify that some of these molecules exhibit liquid–vapour equilibria while others do not. For all of them, we show the morphological phase diagram built up from the different supra-molecular structures formed by each type of trimer. We simulated 14 different systems with a total of 321 states. The main features of the supra-molecular structures depend only on the composition and geometry of the trimer: triple SW trimers do not form supra-structures, double SW trimers and single SW trimers form monolayers, bilayers and worm-like micelles. The liquid–vapour coexistence properties are also exhibited. These trimers can be used to model complex amphiphiles beyond the standard ones, such as the Gemini and the Bola surfactants as well as colloidal particles.