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In this work, we present three donor–acceptor thermally activated delayed fluorescence (TADF) molecules comprising a 2,3,5,6-tetrafluorobenzonitrile acceptor with various electron donor units: phenoxazine (Phx-BzN), phenothiazine (Pht-BzN), and carbazole (Cz-BzN). These molecules have been studied using steady-state and time-resolved photophysical techniques in solution, film in polymer host and in crystal state. While Cz-BzN displays TADF in solution and polymethyl methacrylate (PMMA) films, Phx-BzN and Pht-BzN are non-emissive in solution and somewhat emissive in polymer films. More interestingly, while Pht-BzN remains virtually non-emissive in all studied solvents, it exhibits strong photoluminescence and TADF in crystal state, attributed to Crystallization Induced Emission (CIE). Interestingly, by applying ultrasound to an amorphous Pht-BzN water suspension we were also able to induce a reorganization of the molecules obtaining a microcrystal suspension. This can represents a new strategy to develop luminescent organic microcrystalline materials. We demonstrate through computational studies that the CIE properties arise due to intermolecular interactions in the crystal structure that result in locking the ground state molecular geometry and blocking relaxation in the excited state. As a result, the oscillator strength in the crystal form is enhanced leading to a highly luminescent behaviour, while in solution it equals nearly zero due to the molecule adopting a perfectly orthogonal D–A orientation in the excited state. [ABSTRACT FROM AUTHOR]

We introduce an innovative theoretical framework tailored for the analysis of Pair Distribution Function (PDF) data derived from Small-Angle X-ray Scattering (SAXS) measurements of core-shell micelles. The new approach involves the exploitation of the first derivative of the PDF and the derivation of analytical equations to solve the core-shell micelle structure under the hypothesis of a spheroidal shape. These analytical equations enable us to determine the micelle's aggregation number, degree of ellipticity, and contrast in electron density between the core-shell and shell-buffer regions after having determined the whole micelle size and its shell size from the analysis of the first derivative of the PDF. We have formulated an overdetermined system of analytical equations based on the unknowns that characterize the micelle structure. This allows us to establish a Figure of Merit, which is utilized to identify the most reliable solution within the system of equations. [ABSTRACT FROM AUTHOR]

Chitin, a ubiquitous biopolymer, holds paramount scientific and economic significance. Historically, it has been primarily isolated from marine crustaceans. However, the surge in demand for chitin and the burgeoning interest in biopolymers have necessitated the exploration of alternative sources. Among these methods, the mulberry silkworm (Bombyx mori) has emerged as a particularly intriguing prospect. To isolate chitin from Bombyx mori, a chemical extraction methodology was employed. This process involved a series of meticulously orchestrated steps, including Folch extraction, demineralization, deproteinization, and decolorization. The resultant chitin was subjected to comprehensive analysis utilizing techniques such as attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR), 13C nuclear magnetic resonance (NMR) spectroscopy, and wide-angle X-ray scattering (WAXS). The obtained results allow us to conclude that the Bombyx mori represents an attractive alternative source of α-chitin. [ABSTRACT FROM AUTHOR]

Acrylonitrile‐butadiene‐styrene (ABS) based composites with a high content of tungsten and bismuth oxide were developed using an innovative process to obtain lead‐free x‐ray shielding materials. ABS was chosen for its good mechanical properties and its widespread availability as a recycled material. The composites underwent flexural tests, Shore D hardness tests, thermogravimetric and morphological analysis, and their x‐ray attenuation properties were determined through numerical simulations and experimental measurements. Despite their high filler content (up to 75 wt%), the composites showed good filler dispersion within the polymeric matrix and maintained their mechanical properties. Across the investigated energy range (50–150 kV), the lead equivalence for x‐ray shielding was achieved with composite plates containing 75 wt% of tungsten and bismuth oxide, at thickness values corresponding to a weight increase of only 29% and 36%, respectively, in comparison to lead. These findings pave the way for a new generation of lead‐free x‐ray shielding materials. Moreover, their mechanical properties, including flexibility for potential application in wearable personal protective equipment, can be tailored by adjusting the filler content. Highlights: High filler content lead‐free ABS composites with WO3 and Bi2O3 were developed.They show good polymer/filler interfacial adhesion and flexural properties.Numerical simulations of their x‐ray shielding properties were performed.Experimental tests with polychromatic sources confirmed good x‐ray attenuation.Results pave the way for the development of new lead‐free x‐ray shielding systems. [ABSTRACT FROM AUTHOR]

Flexible perovskite solar cells are lightweight, bendable, and applicable to curved surfaces. Polyethylene terephthalate (PET) has become the substrate of choice compared to other plastic substrates like polyethylene naphthalate. PET is not only stable but also much cheaper to manufacture, an important factor for photovoltaics (PV). Herein, highly efficient devices on PET are demonstrated using a dual low‐temperature (≤100 °C) approach, first by anion mixing (replacing I with Br) of the lead‐containing perovskite composition, increasing bandgap (42% improvement), and then by interfacial engineering with tetrabutylammonium bromide (TBAB) (a further 26% improvement), reaching efficiencies of 28.9% at 200 lx and a record 32.5% at 1000 lx. The TBA+ cation intercalates into the structure, substituting formamidinium cations at the perovskite/TBAB interface, inducing the formation of large‐sized, lower dimensional structures over the 3D perovskite matrix. The resulting PV cell has 1.4 times higher carrier lifetime, one order of magnitude lower leakage currents, and 3 times lower defect densities, suppressing recombination. Importantly, stability (ISOS‐D1 protocol) improves by more than double with treatment. Highly efficient and stable cells on PET films enable seamless integration with wearable, portable, smart building, and Internet of Things electronic devices, expanding the reach of indoor applications. [ABSTRACT FROM AUTHOR]

Type I collagen physiological scaffold for tissue regeneration is considered one of the widely used biomaterials for tissue engineering and medical applications. It is hierarchically organized: five laterally staggered molecules are packed within fibrils, arranged into fascicles and bundles. The structural organization is correlated to the direction and intensity of the forces which can be loaded onto the tissue. For a tissue-specific regeneration, the required macro- and microstructure of a suitable biomaterial has been largely investigated. Conversely, the function of multiscale structural integrity has been much less explored but is crucial for scaffold design and application. In this work, collagen was extracted from different animal sources with protocols that alter its structure. Collagen of tendon shreds excised from cattle, horse, sheep and pig was structurally investigated by wide- and small-angle X-ray scattering techniques, at both molecular and supramolecular scales, and thermo-mechanically with thermal and load-bearing tests. Tendons were selected because of their resistance to chemical degradation and mechanical stresses. The multiscale structural integrity of tendons' collagen was studied in relation to the animal source, anatomic location and source for collagen extraction. [ABSTRACT FROM AUTHOR]

High-dimensionality Ruddlesden-Popper (RP) perovskites, with general formula R2An-1BnX3nþ1 and high n values (n =5), are regarded as viable materials for photovoltaics because they feature higher stability if compared to the 3D perovskite, i.e., ABX3, still maintaining good charge absorption and transport properties. When integrated into the actual solar cells, however, scattered, sometimes contradictory results are reported among different deposition procedures and different cations, especially for higher n resulting in not uniformmorphology and mixed composition. Herein, high-dimensionality RP perovskites with n = 1, 4, 10, 20, and 40 values are systematically investigated considering the interplay between the formation of 2D domains, their distribution along the active layer, the active layer thickness, and the solar cells' performance. Given the complexity of the investigated system, combined advanced structural/morphological analyses are performed to explain solar cells' performance, finding that the 2D phase segregates at the interface with the top electrode, acting as a barrier for charge extraction, overall decreasing the shortcircuit current (Jsc). Reducing the relative amount of bulky alkylammonium cation with respect to the methylammonium, the 2D perovskite overlayer is intentionally decreased leading to a recovery of the Jsc values, corroborating the hypothesis. [ABSTRACT FROM AUTHOR]

In the last two decades, fisheries and fish industries by-products have started to be recovered for the extraction of type I collagen because of issues related to the extraction of traditional mammalian tissues. In this work, special attention has been paid to by-products from fish bred in aquaponic plants. The valorization of aquaponic fish wastes as sources of biopolymers would make the derived materials eco-friendlier and attractive in terms of profitability and cost effectiveness. Among fish species, Nile Tilapia is the second-most farmed species in the world and its skin is commonly chosen as a collagen extraction source. However, to the best of our knowledge, no studies have been carried out to investigate, in depth, the age-related differences in fish skin with the final aim of selecting the most advantageous fish size for collagen extraction. In this work, the impact of age on the structural and compositional properties of Tilapia skin was evaluated with the aim of selecting the condition that best lends itself to the extraction of type I collagen for biomedical applications, based on the known fact that the properties of the original tissue have a significant impact on those of the final product. Performed analysis showed statistically significant age-related differences. In particular, an increase in skin thickness (+110 µm) and of wavy-like collagen fiber bundle diameter (+3 µm) besides their organization variation was observed with age. Additionally, a preferred collagen molecule orientation along two specific directions was revealed, with a higher fiber orientation degree according to age. Thermal analysis registered a shift of the endothermic peak (+1.7 °C) and an increase in the enthalpy (+3.3 J/g), while mechanical properties were found to be anisotropic, with an age-dependent brittle behavior. Water (+13%) and ash (+0.6%) contents were found to be directly proportional with age, as opposed to protein (−8%) and lipid (−10%) contents. The amino acid composition revealed a decrease in the valine, leucine, isoleucine, and threonine content and an increase in proline and hydroxyproline. Lastly, fatty acids C14:0, C15:0, C16:1, C18:2n6c, C18:3n6, C18:0, C20:3n3, and C23:0 were revealed to be upregulated, while C18:1n9c was downregulated with age. [ABSTRACT FROM AUTHOR]

In this work we have studied in situ the formation and growth of calcium phosphate (CaP) nanoparticles (NPs) in the presence of three calcium-binding carboxylate molecules having different affinities for Ca2+ ions: citrate (Cit), hydroxycitrate (CitOH), and glutarate (Glr). The formation of CaP NPs at several reaction temperatures ranging from 25 °C to 80 °C was monitored in situ through simultaneous Small and Wide X-ray Scattering (SAXS/WAXS) using synchrotron light. SAXS was used to investigate the first stages of NP formation where a crystalline order is not yet formed. In this regard we have developed a new bivariate mesh data analysis method for identifying the SAXS curves associated with the most relevant timeframes for performing curve modeling. WAXS was used to study the formation of crystalline phases and their evolution over time. The combined SAXS/WAXS data allowed us to track NP nucleation, their size and morphology, and their evolution up to mature hydroxyapatite (HA) nanocrystals. We have assessed that in the first stages of reaction (80 seconds) amorphous, elongated primary NPs nucleate whose size and morphology depend on the temperature and type of carboxylate molecule. The temperature controls the release of Ca2+ ions from carboxylate molecules, and thus induces the formation of a higher amount of amorphous particles and increases their size and aspect ratio. As the reaction time progresses, amorphous particles evolve into crystalline ones, whose kinetics of crystal growth are controlled by temperature and carboxylate ions. Stronger Ca-binding carboxylates (CitOH > Cit > Glr) have a more pronounced inhibiting effect on HA crystallization, retarding the formation and growth of crystalline domains, while a rise of temperature promotes crystallization. This work allowed us to shed more light on the formation of HA in the presence of growth-controlling molecules, as well as present the potential of combined SAXS/WAXS for studying the formation of highly relevant NPs for different applications. [ABSTRACT FROM AUTHOR]

Abstract In this work the synthesis and characterization of gold nanoparticles functionalized by a novel thiol-organometallic complex containing Pd(II) centers is presented. Pd(II) thiol,trans, trans-[dithiolate-dibis(tributylphosphine)dipalladium(II)-4,4′-diethynylbiphenyl] was synthesized and linked to Au nanoparticles by the chemical reduction of a metal salt precursor. The new hybrid made of organometallic Pd(II) thiol-gold nanoparticles, shows through a single S bridge a direct link between Pd(II) and Au nanoparticles. The size-control of the Au nanoparticles (diameter range 2–10 nm) was achieved by choosing the suitable AuCl4 −/thiol molar ratio. The size, strain, shape, and crystalline structure of these functionalized nanoparticles were determined by a full-pattern X-ray powder diffraction analysis, high-resolution TEM, and X-ray photoelectron spectroscopy. Photoluminescence spectroscopy measurements of the hybrid system show emission peaks at 418 and 440 nm. The hybrid was exposed to gaseous NO x with the aim to evaluate the suitability for applications in sensor devices; XPS measurements permitted to ascertain and investigate the hybrid –gas interaction.

Generated by a hierarchical and multiscale self-assembling phenomenon, peptide-based hydrogels (HGs) are soft materials useful for a variety of applications. Short and ultra-short peptides are intriguing building blocks for hydrogel fabrication. These matrices can also be obtained by mixing low-molecular-weight peptides with other chemical entities (e.g., polymers, other peptides). The combination of two or more constituents opens the door to the development of hybrid systems with tunable mechanical properties and unexpected biofunctionalities or morphologies. For this scope, the formulation, the multiscale analysis, and the supramolecular characterization of novel hybrid peptide-polymer hydrogels are herein described. The proposed matrices contain the Fmoc-FF (Nα-fluorenylmethyloxycarbonyl diphenylalanine) hydrogelator at a concentration of 0.5 wt% (5.0 mg/mL) and a diacrylate α-/ω-substituted polyethylene-glycol derivative (PEGDA). Two PEGDA derivatives, PEGDA 1 and PEGDA2 (mean molecular weights of 575 and 250 Da, respectively), are mixed with Fmoc-FF at different ratios (Fmoc-FF/PEGDA at 1/1, 1/2, 1/5, 1/10 mol/mol). All the multicomponent hybrid peptide-polymer hydrogels are scrutinized with a large panel of analytical techniques (including proton relaxometry, FTIR, WAXS, rheometry, and scanning electronic microscopy). The matrices were found to be able to generate mechanical responses in the 2–8 kPa range, producing a panel of tunable materials with the same chemical composition. The release of a model drug (Naphthol Yellow S) is reported too. The tunable features, the different topologies, and the versatility of the proposed materials open the door to the development of tools for different applicative areas, including diagnostics, liquid biopsies and responsive materials. The incorporation of a diacrylate function also suggests the possible development of interpenetrating networks upon cross-linking reactions. All the collected data allow a mutual comparison between the different matrices, thus confirming the significance of the hybrid peptide/polymer-based methodology as a strategy for the design of innovative materials. [ABSTRACT FROM AUTHOR]

In 2021, Wide-angle X-ray Scattering (WAXS) was applied to a sample of the Turin Shroud as a new method for dating ancient linen threads by inspecting their structural degradation. The major result of the research was to estimate the natural aging of the linen of the Shroud, through which it was found to be compatible with the hypothesis of a 2000-year-old relic, and not a medieval fabric. The present work regards the theoretical natural aging of the linen versus different alleged historical–geographical paths of the Shroud through cities where the presence of icons of Jesus Christ is attested. The theoretical results of the natural aging of the Shroud, calculated for the year 2021, agree extremely well with the experimental results for at least one alleged path. The results also show that if the Shroud were medieval and kept in Europe for 7 centuries, natural aging that is one order of magnitude less than that measured by WAXS would have resulted. Today, the Shroud is kept in a reliquary with a controlled atmosphere, at 19~20 °C temperature, and 50% relative humidity. These values are shown to be unsuitable for maintaining the depolymerization of the cellulose at a level that is sufficiently low enough to preserve the image visible on the Shroud for a long time. [ABSTRACT FROM AUTHOR]