The Influence of Edible Oils’ Composition on the Properties of Beeswax-Based Oleogels

This study aimed to find relationships between the properties of beeswax-based oleogels and the type of oil used. The influence of linseed, sunflower, olive, and fish oils was studied. For these oils, the fatty acid composition, the content of total polar components, and the iodine value were characterized. Textural and thermodynamic properties were determined for oleogels, the oil-binding capacity was estimated, and the morphology of crystals was studied. The concentration of beeswax in all oleogels was 6.0% w/w. It was shown that the type of oil has a significant influence on all characteristics of the oleogels. The use of different oils at the same technological treatment leads to the formation of crystals of diverse morphology—from platelets to spherulites. At the same time, it was revealed that some characteristics of oils have a varying contribution to the properties of oleogels. The content of total polar materials in oils is associated with a decrease in strength parameters (yield value and elastic modulus) and the oil-binding capacity of oleogels. In its turn, the iodine value of oils has a close positive correlation with the melting and crystallization temperatures of oleogels. The results obtained in this article indicate that the properties of beeswax-based oleogels can be directed by changing the oil composition.

Raman Spectra of Bulk and Few-Layer GeSe From First-Principles Calculations

Raman spectra play a significant role in the study of polar materials. Herein, we report the influence of strain and interlayer shift on vibration responses in bulk and few-layer ferrovalley material GeSe in different polarization states (ferroelectric/FE and antiferroelectric/AFE) based on density functional theory and density functional perturbation theory calculations. We find Ag1 mode shifts by about 10 cm−1 from monolayer to bilayer and trilayer due to the interlayer coupling. The Ag3 mode on behalf of FE mode is observed that is consistent with the experiments in bulk and few-layer GeSe. Meanwhile, in our calculations, with the transition between AFE and FE state in the bilayer and trilayer, the Raman frequency of Ag2 and Ag3 mode decrease obviously whereas that of Ag1 mode increases. Interestingly, the Raman peaks shifted a lot due to the strain effect. We expect these variations in the Raman spectroscopy can be employed to identify the status of GeSe films, e.g., the AFE or FE state, and the number of layers in experiments.

Polarity-dependent nonlinear optics of nanowires under electric field

Polar materials display a series of interesting and widely exploited properties owing to the inherent coupling between their fixed electric dipole and any action that involves a change in their charge distribution. Among these properties are piezoelectricity, ferroelectricity, pyroelectricity, and the bulk photovoltaic effect. Here we report the observation of a related property in this series, where an external electric field applied parallel or anti-parallel to the polar axis of a crystal leads to an increase or decrease in its second-order nonlinear optical response, respectively. This property of electric-field-modulated second-harmonic generation (EFM-SHG) is observed here in nanowires of the polar crystal ZnO, and is exploited as an analytical tool to directly determine by optical means the absolute direction of their polarity, which in turn provides important information about their epitaxy and growth mechanism. EFM-SHG may be observed in any type of polar nanostructures and used to map the absolute polarity of materials at the nanoscale.

Off-line analysis in the manganese catalysed epoxidation of ethylene-propylene-diene rubber (EPDM) with hydrogen peroxide

Epoxidation of ethylene-propylene-diene rubber (EPDM), based on 5-ethylidene-2-norbornene, to epoxidized EPDM (eEPDM) opens routes to cross-linking and reactive blending, with increased polarity aiding adhesion to polar materials such as silica.

Effect of Properties of Silver Nanoparticles Coated with Polar Material and the Antibacterial Activity on Marine Pathogenic Bacteria

Silver nanoparticles (Ag NPs) have become one of the current research hotspots and are used in many fields such as electrochemistry, energy, bioanalysis, and environmental monitoring, especially in the field of antibacterial research. In this study, we investigated the effect of properties of Ag NPs coated with polar materials. Ag NPs covered by a dispersant that was triethylene glycol monoethyl ether was stable and conquered the aggregation of Ag NPs. The effect of the dispersant on biocompatibility was explored through interaction experiments between Ag NPs and DNA sequence. The coated Ag NPs could adsorb DNA, and the fluorescence of FAM-DNA could be quenched by Ag NPs. The adsorption and desorption experiments of DNA showed that the order of DNA functional groups on the interaction process was phosphate>T>C>A>G. Moreover, we selected marine pathogenic bacteria to test the antibacterial effect of Ag NPs coated with a polar dispersant. The polar material had a certain inhibitory effect on the antibacterial activity of Ag NPs. However, small molecules such as bases could interact on the surface Ag NPs and release Ag+ to perform the antibacterial activity. The results could contribute to the further application of Ag NPs.

New Family of Ionic Supersalts with Covalent-like Directionality and Unconventional Multiferroicity

Ionic crystals composed of elemental ions such as NaCl are centro-symmetric and, thus, non-polar due to directionless ionic bonding interactions. To develop polar materials, the directionality feature of covalent bonding is necessary. Here, we propose a novel way where ionically bonded crystals can develop polarity by changing their building blocks from elemental ions to cluster-ions. Superalkalis and superhalogens are clusters which mimic the chemistry of alkali and halogen atoms. Equally important, unlike the elemental ions, the geometries of these superions are not spherical. Endowed with these unique features, ionic supersalts form anisotropic polar structures with ionic bonding, yet covalent-like directionality, akin to sp3 hybridized systems. Using density functional theory and extensive structure searches, we predict a series of stable supersalts, PnH4MX4 (Pn = N, P; M = B, Al, Fe; X = Cl, Br) composed of superalkali PnH4 and superhalogen MX4 ions with unprecedented properties: (1) ferroelectricity with ultra-long ion displacements (~ 3 Å); (2) ferroelasticity with ultra-large reversible strain (> 40%); and (3) both with ultra-low switching barriers (about 6 to 13 meV/atom). These values are inconceivable in traditional ferroelectric/ferroelastic materials owing to their brittle covalent nature. Coupling of ferroelectricity with ferroelasticity can further enable strain-controlled polarization as well as electrically-controlled strain. In particular, PnH4FeX4 exhibits triferroic coupling of ferroelectricity, ferroelasticity, and antiferromagnetism where the spin directions can be altered via either ferroelastic or 90-degree ferroelectric switching. These ionic supersalts can be synthesized using facile solution-processed fabrication by exothermic reactions, MPn + 4HX→PnH4MX4 or PnH4X + MX3→PnH4MX4, which may open a new chapter in multiferroics.