Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux

Carbon-based benzvalene undergoes diverse rearrangements upon exposure to external stimuli. In this report, we investigate the thermal and metal-catalyzed rearomatization pathways of BN-benzvalene, a boron-nitrogen-containing valence isomer of benzene. Depending on the choice of metal catalyst, these transformations selectively yield either C5- or C3-functionalized 1,2-azaborines. The C5-isomer formation serves as a proof of concept for a new molecular photoswitch system, while the C3-isomer formation represents the functional group transposition on the 1,2-azaborine scaffold. Mechanistic investigations, such as deuterium labeling studies and DFT calculations, suggest distinct operative pathways for the generation of each isomer.

Converting pre-existing gas storage facilities to dihydrogen storage raises critical questions about storage quality and dihydrogen consumption by prokaryotes. To investigate biologically driven changes during such transitions, we analyzed data from five dihydrogen pulse experiments conducted in pressurized bioreactors that replicate deep aquifer pressure and temperature conditions. Our goal was to determine whether consistent community-level responses to dihydrogen injection could be identified. We found that dihydrogen exposure consistently led to a decline in fermentative ASVs, likely driven by environmental filtering. Hydrogenotrophic sulfate reducers initially dominated in some experiments, with total sulfate depletion observed in certain cases, followed by the emergence of methanogenic archaea. In some instances, a succession pattern involving Thermodesulfovibrio and Methanothermobacter appeared across taxonomically distinct communities, suggesting deterministic ecological processes. Additionally, we observed potential dispersal limitation and selection pressures, possibly linked to pH shifts caused by autotrophy. These findings underscore the importance of considering microbial dynamics in dihydrogen storage strategies in deep aquifers and suggest that, despite initial variability, predictable ecological succession may occur under specific geochemical conditions.

ABSTRACT This computational study investigates π‐conjugated structures based on dibenzothiophene (DBT) for high‐performance organic photovoltaics (OPVs). Leveraging experimental evidence highlighting DBTs promising optoelectronic properties, we conduct a systematic computational evaluation of modified DBT architectures. Density functional theory (DFT) calculations using Gaussian 09 were employed to optimize molecular geometries in gas and liquid phases. To identify the most accurate method for modeling electronic properties, we compare functionals (B3LYP, CAM‐B3LYP, MPW1PW91, and wB97XD) with the 6‐31G(d,p) basis set. For solid‐state simulations, CRYSTAL software with B3LYP/6‐31G(d,p) ensured consistency between isolated‐molecule and crystalline‐environment predictions. Four derivatives (M1–M4) with distinct substituted cores were analyzed via DFT/B3LYP/6‐31G(d,p). This method was used to discuss characteristics, including gap energy, frontier molecular orbitals, reactivity indices, exciton binding energy, reorganization energies, electrostatic potential, density of states, and photovoltaic parameters such as open‐circuit voltage, short‐circuit current, and fill factor with PC 61 BM as acceptor. We also obtained UV/Visible absorption wavelengths ( λ max ), excitation energies, oscillator strengths, dipole moments, and light‐harvesting efficiencies in both chloroform and gaseous phases. Every computed characteristic points to the potential of our proposed molecules for solar applications.

To reduce the use of toxic and polluting synthetic pigments and dyes, which are still common in industry, marine biomimicry has inspired the development of functional hybrid materials to enhance the photoresistance of natural pigments. This is a key factor limiting their industrial use. Herein, we propose to develop a new type of photostable hybrid pigment, inspired by the biomineralization process of calcium carbonate (CaCO3), which traps natural organic dyes within sea urchin spines. Alizarin (polyhydroxyanthraquinone, AZ) was selected to mimic organic chromophores present in sea urchins, i.e. polyhydroxynaphthoquinone. The biomacromolecules chitosan (CS) and α-poly-l-lysine (PLL) were used to imitate the organic matter involved in CaCO3 biomineralization in sea urchins, thanks to their abundance of amine groups (-NH2). Using a straightforward coprecipitation method under gentle conditions, it was shown that AZ dye molecules became embedded in a CaCO3 shell, thereby shielding them from photodegradation. It has been demonstrated that chitosan effectively aids in the coprecipitation process by stabilizing the vaterite polymorph, while α-poly-l-lysine has little impact on CaCO3 formation. To extend the potential of these hybrid pigments for applications such as UV-protective films for food packaging, self-supporting CaCO3/chitosan (CaCO3/CS) composite films and tinted hybrid pigment/chitosan (CaCO3-AZ/CS) films were developed, leveraging the excellent film-forming properties of chitosan. Different quantities of CaCO3(-AZ) particles were incorporated into the formulations to tailor the films' mechanical and optical characteristics.

In this work, a protocol for evaluating the long-term thermal and chemical stability of capric acid is presented. Capric acid is a phase change material (PCM) employed as a latent heat thermal storage material to store/retrieve heat during the phase transition from solid to liquid or vice versa. The nature of the materials utilized for latent heat thermal batteries plays a vital role in their long-term performance for the different applications. Therefore, precisely investigating these material thermal and chemical stability is significant. The protocol consists of two tests (accelerated thermal cycling and thermal stress) in which the performance of the PCM will be investigated. A benchmark experiment for accelerated thermal cycling was performed where the impact of different parameters (heating/cooling rate and sample volume) was investigated for the initial 50 thermal cycles. This was followed by long-term accelerated thermal cycling for a total of 1500 thermal cycles (melting followed by crystallization). A thermal stress where the PCM stays in a liquid state was performed for the capric acid to investigate the impact of the higher temperature on the stability of the PCM. The thermal properties reliability over time was measured with differential scanning calorimetry (DSC), which indicated a variation of 3.2 % in onset phase change equilibrium temperature and 10.45 % in phase change enthalpy after 1500 thermal cycles. Gas chromatography (GC) and nuclear magnetic resonance spectroscopy (NMR) were performed to reveal that by-products are formed during capric acid thermal treatment. These results provide valuable guidance for the research community to design adapted thermal cycling protocols and select appropriate characterization methods, thereby enabling more accurate and reliable investigations of the long-term stability of organic PCMs. • Accelerated thermal cycling and Thermal stress test for capric acid • Investigated the impact of heating/cooling rate and volume of sample • After 1500 thermal cycles the variation in T m(onset) and ∆ fus H was 3.2 % and 10.45 % respectively • By-products formed during the thermal cycling were detected with NMR and GC. • The by-products were identified as Octanoic acid, heptly ester, and Heptadecane.

Abstract As perovskite solar cells (PSCs) advance toward commercialization, the need for stable and easily processable materials becomes increasingly important. In this study, we examine how the aging of polymeric electron transport layers (ETLs) affects the performance of inverted PSCs. Two main‐chain poly(fullerene)s, PC 60 DB (IMP) and PC 60 DB (ATRAP) , which differ only in their terminal halogen groups, were stored under nitrogen, in the dark and at room temperature, for up to 11 months before device fabrication. Devices using aged PC 60 DB (IMP) showed significant drops in efficiency, while those based on PC 60 DB (ATRAP) maintained more stable performance and even exhibited reduced hysteresis over time. These contrasting results appear to stem from differences in halogen reactivity, with iodine likely triggering degradation pathways not seen in the bromine‐containing counterpart. Altogether, the findings highlight how thoughtful molecular design can improve the long‐term stability and practical use of ETL materials in scalable PSC technologies. © 2025 The Author(s). Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The thermal response of Carbon Fiber Reinforced Thermoplastic (CFRTP) tapes under short-term localized heating is critical for automated manufacturing processes. Conventional homogenized models often overlook microstructural heterogeneities that can promote non-uniform heating and affect the quality of the consolidated part. In this work, we combine insights from infrared thermography with finite element simulations at the fiber scale built on micrographs extracted from real tapes to quantify the effect of individual heterogeneities—including surface roughness, thickness variation, fiber agglomeration, and porosity—on thermal propagation. Three modeling configurations were compared under identical conditions: a full microstructure model; a simplified geometry-aware model (where the real geometry is taken into the account, including the surface roughness and thickness variability, but the properties of the domain are considered as a homogeneous-equivalent material); and a homogeneous-equivalent baseline with flat borders and uniform thickness. Results show that porosity effects depend strongly on location and orientation: large, horizontally aligned pores near the heated surface produce the highest gradients. Surface roughness, on the other hand, exerts dominant effects on surface temperature non-uniformity with respect to thickness variation and fiber distribution. These findings demonstrate that accounting for microscale heterogeneities is essential to achieve more accurate, optimized, and application-tailored analyses of CFRTP tapes in advanced manufacturing.