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Thin films of styrene copolymers containing fluorescent molecular rotors were demonstrated to be strongly sensitive to volatile organic compounds (VOCs). Styrene copolymers of 2-[4-vinyl(1,1′-biphenyl)-4′-yl]-cyanovinyljulolidine (JCBF) were prepared with different P(STY-co-JCBF)(m) compositions (m% = 0.10–1.00) and molecular weights of about 12,000 g/mol. Methanol solutions of JCBF were not emissive due to the formation of the typical twisted intramolecular charge transfer (TICT) state at low viscosity regime, which formation was effectively hampered by adding progressive amounts of glycerol. The sensing performances of the spin-coated copolymer films (thickness of about 4 µm) demonstrated significant vapochromism when exposed to VOCs characterized by high vapour pressure and favourable interaction with the polymer matrix such as THF, CHCl3 and CH2Cl2. The vapochromic response was also reversible and reproducible after successive exposure cycles, whereas the fluorescence variation scaled linearly with VOC concentration, thus suggesting future applications as VOC optical sensors.

Mechanochromic polymers are defined as materials that are able to detect a mechanical stress through an optical output. This feature has evoked a growing interest in the last decades, thanks to the progress of chromogenic molecules whose optical characteristics and chemical functionalities allow their effective insertion in many thermoplastic and thermoset matrices. Among the different types of fluorogenic probes able to detect mechanical solicitations, those with aggregation-induced emission (i.e., AIEgens) have attracted tremendous interest since their discovery in 2001. In the present review, the main principles behind the AIEgens working behavior are introduced along with the current state of knowledge concerning the design and preparation of the derived mechanochromic fluorescent polymers. Examples are provided concerning the most ingenious solution for the preparation of chromogenic materials, starting from different types of commodity plastics or synthetic polymers and combined with the latest AIE technology to provide the most sensitive response to mechanical stress.

Anion exchange membranes (AEM) have gained attention recently as a promising candidate for low-cost water electrolysis systems to produce hydrogen, linked with renewable energy resources as a sustainable alternative to fossil fuels. The development of potential materials for producing and analyzing AEM is an imperative step towards commercialization and plays a competitive role in the hydrogen production industry. In this article, we developed a composite anion exchange membrane prepared by activating a commercial support structure (Celgard® 3401) with a commercially available functional group (Fumion® FAA-3) through a phase-inversion process. Fourier-transform infrared spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) analysis demonstrated the phase-inversion procedure as an effective methodology. Furthermore, the cell performance test result (with Celgard/Fumion) was very promising and even better in comparison with a commercial membrane commonly applied in alkaline electrolysis (Fumasep). We also developed a testing procedure for membrane performance evaluation during electrolysis which is very critical considering the effect of CO2 absorption on membrane conductivity.

Aggregation‐induced emission (AIE) luminogens are attractive dyes to probe polymer properties that depend on changes in chain mobility and free volume. When embedded in polymers the restriction of intramolecular motion (RIM) can lead to their photoluminescence quantum yield (PLQY) strong enhancement if local microviscosity increases (lowering of chain mobility and free volume). Nonetheless, measuring PLQY during stimuli, i.e. heat or mechanical stress, is technically challenging; thus, emission intensity is commonly used instead, assuming its direct correlation with the PLQY. Here, by using fluorescence lifetime as an absolute fluorescence parameter, it is demonstrated that this assumption can be invalid in many commonly encountered conditions. To this aim, different polymers are loaded with tetraphenylenethylene (TPE) and characterized during the application of thermal and mechanical stress and physical aging. Under these conditions, polymer matrix transparency variation is observed, possibly due to local changes in refractive index and to the formation of microfractures. By combining different characterization techniques, it is proved that scattering can affect the apparent emission intensity, while lifetime measurements can be used to ascertain whether the observed phenomenon is due to modifications of the photophysical properties of AIE dyes (RIM effect) or to alterations in the matrix optical properties.

Foot ulcers account for 15% of comorbidities associated with diabetes. Presently, no device allows the status of foot ulcers to be continuously monitored when patients are not hospitalized. In this study, we describe a temperature and a pH sensor capable of monitoring diabetic foot and venous leg ulcers developed in the frame of the seventh framework program European Union project SWAN-iCare (smart wearable and autonomous negative pressure device for wound monitoring and therapy). Temperature is measured by exploiting the variations in the electrical resistance of a nanocomposite consisting of multiwalled carbon nanotubes and poly(styrene-b-(ethylene- -butylene)-b-styrene). The pH sensor used a graphene oxide (GO) layer that changes its electrical potential when pH changes. The temperature sensor has a sensitivity of ~85 Ω/°C in the range 25°C-50°C and a high repeatability (maximum standard deviation of 0.1% over seven repeated measurements). For a GO concentration of 4 mg/mL, the pH sensor has a sensitivity of ~42 mV/pH and high linearity (R2=0.99).

A typical halogen-free flame-retardant (HFFR) formulation for electric cables may contain polymers, various additives, and fire-retardant fillers. In this study, composites are prepared by mixing natural magnesium hydroxide (n-MDH) with linear low-density polyethylene (LLDPE) and a few types of ethylene–octene copolymers (C8-POE). Depending on the content of LLDPE and C8-POE, we obtained composites with different crystallinities that affected the final mechanical properties. The nucleation effect of the n-MDH and the variations in crystallinity caused by the blending of C8-POE/LLDPE/n-MDH were investigated. Notably, in the C8-POE/LLDPE blend, we found a decrease in the crystallization temperature of LLPDE compared to pure LLDPE and an increase in the crystallization temperature of C8-POE compared to pure C8-POE. On the contrary, the addition of n-MDH led to an increase in the crystallization temperature of LLDPE. As expected, the increase in the crystallinity of the polyolefin matrix of composites led to higher elastic modulus, higher tensile strength, and lower elongation at break. It has been observed that crystallinity also influences fire performance. Overall, these results show how to obtain the required mechanical features for halogen-free flame-retardant compounds for electric cable applications, depending on the quantities of the two miscible components in the final blend.

Organic fluorophores have found broad application as emitters in luminescent solar concentrators (LSCs) for silicon photovoltaics. In particular, the preparation of organic conjugated systems with intense light-harvesting ability, emissions in the deep-red and NIR regions, and large Stokes shift values represent a very challenging undertaking. Here, we report a simple and easy way to prepare three symmetrical donor–acceptor–donor (DAD) organic-emitting materials based on a thienopyrazine core. The central core in the three dyes was modified with the introduction of aromatic substituents, aiming to affect their optical properties. The fluorophores were characterized by spectroscopic studies. In all cases, visible-NIR emissions with large Stokes shifts were found, highlighting these molecules as promising materials for the application in LSCs.

This study examines the use of an aggregation‐induced enhanced emission fluorophore (TPE‐MRh) to prepare red‐emitting luminescent solar concentrators (LSCs) based on poly(methyl methacrylate) (PMMA) and poly(cyclohexyl methacrylate) (PCMA). TPE‐MRh is a tetraphenylethylene (TPE) derivative bearing two dimethylamino push groups and a 3‐methyl‐rhodanine pull moiety, with absorption maxima at around 500 nm and fluorescence peak at 700 nm that strongly increases in solid‐state. TPE‐MRh displays a typical crystallization‐induced enhanced emission that has been rationalized by modeling the compound behavior in solution and solid‐state via density functional theory calculations with the inclusion of the environment. TPE‐MRh dispersed into 5 × 5 cm2 polymer films with a thickness of 25 ± 5 μm has revealed a partial fluorescence quenching with fluorophore content. Quantum yields (QYs) below 10% for the 2 wt.% of doping have been addressed to the formation of less emissive micro‐sized clusters of fluorophores. PMMA slabs with the same surface size but 3 mm of thickness and 200 ppm of TPE‐MRh have provided QY of 36.5% thanks to the attenuation of the detrimental effects of fluorophore aggregation. This feature is reflected in the LSCs performance, with devices achieving the largest power collected by the photovoltaic cell. A new red‐emitting push‐pull tetraphenylethylene (TPE)‐derivative (TPE‐MRh) with aggregation‐induced enhanced emission and crystallization‐induced enhanced emission features is prepared and studied in solution and in the solid‐state by spectroscopic and computational investigations at the density functional theory level. TPE‐MRh properties open its use in thin‐film and slab luminescent solar concentrators.

Background The thalamus plays a central role in the pathophysiology of migraine, particularly through its involvement in the thalamocortical network. Structural changes in this region may underlie the altered sensory processing observed in migraine. This study aimed to assess volumetric differences in the thalamus and its subregions between patients with episodic migraine without aura and healthy controls, using MRI acquired during the interictal phase. Methods Thirty patients with episodic migraine without aura (MO) and 30 healthy controls (HCs) of comparable age and sex underwent high-resolution T1-weighted MRI and full ophthalmological evaluation. All patients were scanned during the interictal phase and were not receiving preventive treatment. Volumetric segmentation made using FreeSurfer’s automatic segmentation software (v7.4.1) included the entire thalamus and 25 subregions. General linear models were used to assess volumetric differences, controlling for age, sex, and total intracranial volume. Results No statistically significant differences were found in the total thalamic volume or in any of its subregions between MO patients and HCs (p uncorrected >0.05). Moreover, no correlations emerged between thalamic volumes and clinical characteristics of migraine (attack frequency, attack duration, severity of pain, HIT-6, MIDAS, ASC-12, and days since the last attack, p FDR corrected >0.05). No relevant ophthalmological abnormalities were detected. Conclusions Our findings suggest that thalamic macroscopic volumes are not altered during the interictal phase in patients with MO and without relevant ocular abnormalities. Complementary approaches—such as functional or microstructural imaging—may be required to further elucidate thalamic involvement in migraine pathophysiology.