Flame retardant epoxy is closely related to the safety of a human's life against the surrounding fire threat. Flame retardant properties can be obtained by supplementing with additives, such as phosphorus compounds and nanomaterials, or synthesizing flame retardant monomers. The principle of improving flame retardancy is based on the capture of oxygen radicals and the formation of a char layer, which blocks flammable gases. This paper focuses on a flame retardant epoxy resin using naturally occurring tannic acid (TA) as a hardener, which is both an oxygen-radical quencher and a charring agent. TA is reacted with the commercially available diglycidyl ether of bisphenol A (DGEBA). The reaction between the epoxy ring of the DGEBA and multiple functional groups in TA is empirically demonstrated using dynamic scanning calorimetry (DSC) and Brillouin spectra. The most effective flameretardant TA-DGEBA (TD) thermoset had an limiting oxygen index (LOI) value 46% higher than the control sample. This result suggests that TA-based epoxy resins could be promising flame-retardant polymers.

We performed terahertz time-domain spectroscopy, low-frequency Raman scattering, and Brillouin light scattering on vitreous glucose to investigate the boson peak (BP) dynamics. In the spectra of α(ν)/ν 2 [α(ν) is the absorption coefficient], the BP is clearly observed around 1.1 THz. Correspondingly, the complex dielectric constant spectra show a universal resonancelike behavior only below the BP frequency. As an analytical scheme, we propose the relative light-vibration coupling coefficient (RCC), which is obtainable from the combination of the far-infrared and Raman spectra. The RCC reveals that the infrared light-vibration coupling coefficient C IR (ν) of the vitreous glucose behaves linearly on frequency which deviates from Taraskin

PbHfO(3) is investigated theoretically and experimentally with respect to possible precursor effects starting in the paraelectric phase far above the cubic to tetragonal phase transition temperature. The theoretical modeling within the polarizability model predicts a giant softness of the system with spatially large polar and antiferrodistortive domain formation which compete with each other. These predictions are substantiated by the experiments, where the softness and the precursor effects are confirmed by birefringence, dielectric permittivity measurements and elastic properties by Brillouin scattering. The intermediate phase is found to have the polar nature confirmed by P-E hysteresis loop measurements, which is another manifestation of the competition between interrelated instabilities, namely a polar one and an antiferroelectric one.

N‐type metal oxides such as hematite (α‐Fe2O3) and bismuth vanadate (BiVO4) are promising candidate materials for efficient photoelectrochemical water splitting; however, their short minority carrier diffusion length and restricted carrier lifetime result in undesired rapid charge recombination. Herein, a 2D arranged globular Au nanosphere (NS) monolayer array with a highly ordered hexagonal hole pattern (hereafter, Au array) is introduced onto the surface of photoanodes comprised of metal oxide films via a facile drying and transfer‐printing process. Through plasmon‐induced resonance energy transfer, the Au array provides a strong electromagnetic field in the near‐surface area of the metal oxide film. The near‐field coupling interaction and amplification of the electromagnetic field suppress the charge recombination with long‐lived photogenerated holes and simultaneously enhance the light harvesting and charge transfer efficiencies. Consequently, an over 3.3‐fold higher photocurrent density at 1.23 V versus reversible hydrogen electrode (RHE) is achieved for the Au array/α‐Fe2O3. Furthermore, the high versatility of this transfer printing of Au arrays is demonstrated by introducing it on the molybdenum‐doped BiVO4 film, resulting in 1.5‐fold higher photocurrent density at 1.23 V versus RHE. The tailored metal film design can provide a potential strategy for the versatile application in various light‐mediated energy conversion and optoelectronic devices.