Changes In Crystallinity Research Articles

Anti-solvent materials enhanced structural and optical properties on ambiently fabricated perovskite thin films

Perovskite solar cells (PSCs) hold potential for low-cost, high-efficiency solar energy, but their sensitivity to moisture limits practical application. Current fabrication requires controlled environments, limiting mass production. Researchers aim to develop stable PSCs with longer lifetimes under ambient conditions. In this research work, we investigated the stability of perovskite films and solar cells fabricated and annealed in natural air using four different anti-solvents: toluene, ethyl acetate, diethyl ether, and chlorobenzene. Films (about 300 nm thick) were deposited via single-step spin-coating and subjected to ambient air-atmosphere for up to 30 days. We monitored changes in crystallinity, electrical properties, and optics over time. Results showed a gradual degradation in the films’ crystallinity, morphology, and electro-optical properties. Notably, films made with ethyl acetate exhibited superior stability compared to other solvents. These findings contribute to advancing stable and high-performance PSCs manufactured under normal ambient conditions. In addition, we also discuss the possible machine learning (ML) approach to our future work direction to optimize the materials structures, and synthesis process parameters for future high-efficient perovskite solar cells fabrication.

Dissolution of denim waste in N-methyl morpholine-N-oxide monohydrate for fabrication of regenerated cellulosic film: Experimental and simulation study

Despite the significant amount of denim waste and its potential as a cellulose source, its use has been neglected. This study uses N-methyl morpholine-N-oxide, an eco-friendly solvent, to dissolve denim (including 100 % cotton) and create a denim film. Achieving a 10 % denim record solubility, a cellulosic film was also fabricated for comparison. Characterisation techniques were applied, and molecular dynamics simulations explored intramolecular interactions and the influence of indigo dye on dissolution process. FTIR spectra indicated no chemical reactions during dissolution and regeneration, though a shift in OH stretching suggested a change in crystallinity, confirmed by XRD results showing decreased crystallinity and a structural shift from cellulose I to cellulose II. 13C NMR analysis revealed disruptions in interchain hydrogen bonds after regeneration. TGA results showed lower decomposition temperatures for both films compared to the powders. Testing mechanical properties showed the denim film had higher elongation at break but lower tensile strength than the cellulose film. MD simulations indicated indigo dye did not significantly affect fundamental interactions but decreased denim solubility by reducing the diffusion coefficient. Rheological tests supported the simulation results, showing higher viscosity and molecular weight for the denim solution compared to cellulose.

The effect of polysaccharide type on dielectric barrier discharge (DBD) plasma glycosylation of sodium caseinate-part I: Physicochemical, structural and thermal properties

This study aimed to investigate the impact of polysaccharide type on the physicochemical, structural, and thermal properties of dielectric barrier discharge (DBD) plasma glycosylated sodium caseinate (SC). The polysaccharides Quince seed gum (QSG), carboxymethyl cellulose (CMC), and maltodextrin (MD) were mixed with SC and treated with DBD plasma at 18 kV for 10 min. The grafting degree, electrophoresis pattern, FTIR, XRD, carbonyl, sulfhydryl, and di-tyrosine content, FE-SEM, color, and thermal properties of SC and its polysaccharide mixtures before and after plasma treatment were analyzed. Results showed that the SC-QSG conjugate had the highest glycation degree and color change after plasma treatment. The SC-CMC and SC-QSG conjugates exhibited disappearance of distinct SC bands in electrophoresis pattern compared to SC. Also, significant changes in functional group and crystallinity were occurred in SC-CMC conjugate. Plasma treatment caused oxidation of SC, but the presence of polysaccharides offered protection against oxidation. The microstructure of SC was altered by mixing with polysaccharides and exposure to plasma. Also, the mixtures indicated higher thermal stability after plasma treatment. Results confirmed that the generation of protein-polysaccharide conjugates through DBD plasma technique was depended on with SC-MD conjugate unable to form through this method.

Thermo-pressed blend films of poly(lactic acid)/poly(butylene adipate-co-terephthalate) with polylimonene for sustainable active food packaging

Poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) blends provide sustainable packaging solutions renowned for their robustness and biodegradability. Herein, we used a commercial PLA/PBAT blend (Ecovio® - E) to develop films by thermo-pressing, incorporating polylimonene (PLM) and comparing them with limonene (LIM) at 5% and 10% additive concentrations. Remarkably, E/PLM10% film exhibited an 84.9% reduction in Staphylococcus aureus count and a 62% decrease in Aspergillus niger count, surpassing LIM and PLA/PBAT. Additionally, PLM substantially improved the antioxidant activity of the films, achieving more than 40% DPPH scavenging and providing light-blocking capability, with E/PLM5% virtually halting UV-A transmission. Mechanical assessments showed that, although higher PLM levels reduced tensile strength, E/PLM5% matched control performance. FT-IR analysis confirmed PLM presence without chemical alterations, and minimal changes in crystallinity were observed via DSC and XRD, while TGA confirmed the attractive thermal stability of the films. Expanding on these findings, we evaluated film efficacy in cherry tomato preservation, including unpackaged controls. E/PLM5%-packaged tomatoes exhibited superior visual quality and fungal inhibition, proving a promising option for active food packaging due to their antimicrobial effectiveness, antioxidant activity, and UV-light protection. Therefore, this study represents significant progress in advanced packaging development, providing prolonged food preservation, sustainability, and retained performance even when prepared in simulated industrial conditions.

Adsorption and nucleation mechanism of molten carbonate on nano-SiC surface

Molten carbonate is an important thermal storage media for high temperature thermal energy storage system. However, the specific heat capacity (SHC) of carbonate is less than 2 J/g K, which limits its application prospects. Nano-SiC was used to improve the SHC of carbonate at high temperature in our previous work. The SHC of binary carbonate increased by 83 % with the addition of nano-SiC. However, the improvement mechanism is not clear. In this study, the adsorption and nucleation mechanism of molten carbonate on nano-SiC surface were clarified. The DFT calculation results show that the adsorption energy of Li+, Na+ and CO32− is −310, −259 and −654 kJ/mol, respectively, which means the addition of nano-SiC causes a non-uniform distribution of molten carbonate ions around its surface. This affects the subsequent nucleation and results in carbonate segregation. Na2CO3 is the most thermodynamically favorable to adsorb and nucleate, followed by LiNaCO3, and Li2CO3 is the most difficult. The crystalline phase changes of carbonate on nano-SiC surface from solid to liquid phase during melting process were obtained in-situ and the results are consistent with the DFT calculations. Therefore, the adsorption and nucleation mechanism of molten carbonate on nano-SiC surface is well elucidated by the calculations and experiments of this study.

Chemical changes of polysaccharides in heat-treated European beech wood

This work deals with the influence of different heat treatment temperatures (140, 150, 160, 170, 180, 190, 200, and 210 °C) on changes in sapwood and red heartwood of European beech (Fagus sylvatica L.). According to the results of wet chemistry methods, HPLC (high-performance liquid chromatography), FTIR (Fourier transform infrared spectroscopy), SEC (size exclusion chromatography), the wood constituents in sapwood and red heartwood behaved similarly to heat treatment, but the individual proportions were different. The loss of hemicelluloses and the increase in extractives with increasing temperature were more pronounced in sapwood. The amount of cellulose in sapwood and red heartwood showed similar behaviour with increasing temperature. Thermal treatment causes changes in cellulose crystallinity, and the formation of aromatic structures, mainly in beech sapwood. However, the increase in the lignin content of red heartwood was significantly lower than that of sapwood due to its auto condensation, and formation of pseudo-lignin. Among the carbohydrates, the most significant changes were observed in xylose content, which was almost twice as high in red heartwood as in sapwood. Other carbohydrates (glucose, mannose, galactose, and arabinose) reached similar values in sapwood and red heartwood.

Effect of Mechanical Compression on Ionic Conductivity of PEO-LiTFSI Solid Polymer Electrolytes

In the field of energy storage materials, the development of robust solid polymer electrolytes for lithium-ion batteries necessitates an understanding of ionic conductivity when subjected to mechanical stress. Accurate determination of ionic conductivity requires knowing the electrolyte thickness, which is subject to volumetric changes during charging and discharging of solid-state batteries. However, compressive stress reduces the thickness of the electrolyte by an indeterminate amount.This work presents experimental measurements of ionic conductivity as a function of compressive stress, using poly(ethylene oxide) and with bis(trifluoromethane) sulfonimide (PEO-LiTFSI). In this study, we not only measure the stress-strain response of the electrolytes directly, but also monitor the extent of compression during electrochemical impedance spectroscopy (EIS). Compression was applied up to 50% strain for three consecutive cycles, and the typical thickness for the fabricated electrolytes was ~50 µm. EIS testing was performed by using an impedance analyzer, with the electrolyte placed between stainless steel blocking electrodes. Bulk resistance was determined by equivalent circuit modeling of impedance between 100 Hz and 2 MHz. Ionic conductivity κ was calculated from bulk resistance Rb , electrolyte thickness h, and cross-sectional area A, according to the equation κ = h/(Rb·A).In order to measure both stress and deformation simultaneously, a custom positioning stage was engineered to apply prescribed compression. The apparatus has an in-line load cell for force measurements and a laser triangulation sensor for position tracking with submicron resolution. We found that the bulk resistance at room temperature decreases exponentially, with magnitude reduced by approximately five-fold when subjected to compressive stress up to 10 MPa. Beyond ~7 MPa, bulk resistance values were no longer dependent on the amount of applied compression.In addition to mechanical measurements, changes in crystalline and amorphous regions were correlated to the magnitude of compressive stress and the measured ionic conductivity of the electrolyte. For optical imaging with simultaneous EIS measurements, glass slides coated with an indium tin oxide (ITO) film were used instead of stainless steel disks. The extent of crystallinity was visualized by optical microscopy of spherulites through a viewing window when compressed between rigid plates.Figure 1. Apparatus (left) and representative ionic conductivity vs. compressive stress (right) data for a PEO-LiTFSI polymer electrolyte. Figure 1

Real-Time Monitoring of Electrochemical Reactions in All-Solid-State Lithium Batteries by Simultaneous Grazing-Incidence Small-Angle/Wide-Angle X-Ray Scattering

Polyethylene oxide (PEO)-based composite electrolytes (PCEs) are considered as the promising candidates for next generation lithium metal batteries due to its high safety, easy fabrication and good electrochemical stability. However, the material suffers from low conductivity and high crystallinity of the ethylene oxide (EO) chain, which inhibits its commercialization. Therefore, it is crucial to understand the electrochemcial process as well as Li+ transfer pathway within PEO-based batteries. Using operando grazing-incidence small-angle and wide-angle X-ray scattering (GISAXS and GIWAXS) in Li||Cu cell framework, we find that the electrochemical reaction within the PCE is highly correlated with the evolution of the buried morphology and crystalline structure evolution of the PCE. This two irreversible reactions, PEO-Li+ reduction and TFSI- decomposition, cause changes in both the crystalline structure and morphology of the PCE. In addition, the reversible Li plating/stripping process alters the inner morphology, especially the PEO-LiTFSI domain radius, rather than causing crystalline structure changes. This work provides a new path to monitor a working battery in real time, thereby enabling detailed understanding of electrochemically-induced changes of the microscopic morphology and crystalline structure of PCE, which is essential for developing high transferable and interface stable PCE-based lithium metal batteries. Figure 1

Impact of lignocellulosic nanofiber source on the performance of polylactic acid

AbstractComposites based on polylactic acid (PLA) were developed, using lignocellulosic nanofibers (LCNF) dispersed in polyethylene glycol (PEG). To evaluate the impact of LCNF sources, suspensions were prepared from different pulps, including only cellulose; other with cellulose and hemicellulose; and cellulose, hemicellulose, and lignin. The PLA/PEG ratio was 80/20, with LCNF concentrations of 1.25%, 2.5%, and 3.75% (w/w) relative to the PLA/PEG weight. The best results were achieved with 2.5% (w/w) of LCNF containing a blend of cellulose and hemicellulose, showing a 26% increase in tensile strength and 102% in Young's modulus compared with the PLA/PEG matrix. The hemicellulose in LCNF acts as a physical barrier between cellulose chains, demonstrating a lower tendency for agglomeration and greater compatibility with PEG and PLA, as evidenced by decreased zeta potential due to the adsorption of PEG and shifts in the CO peak in the FTIR spectra. At 3.75 LCNF concentration, micrometer‐sized fibers were observed in SEM images, impacting the mechanical properties of the composites. Thermograms show no phase separation, and the change in crystallinity due to the addition of nanofibers has minimal influence on mechanical properties. These findings highlight the importance of selecting appropriate lignocellulosic nanoparticles for improved material performance.

Influence of nano graphene filler on hardness, impact strength and density of glass epoxy composites

AbstractThis study investigates the effects of graphene reinforcement on the hardness and impact strength of glass epoxy composites. Four different materials were examined: pure epoxy (EP), glass epoxy (GE), glass epoxy with 1 wt.% graphene (GE1), and glass epoxy with 2 wt.% graphene (GE2). The results show that the incorporation of graphene significantly enhances the hardness of the composites. Pure epoxy (EP) exhibited a Shore D hardness of 60 and an impact strength of 0.09 J/m2. The glass epoxy (GE) showed a reduction in hardness to 56 but an increased impact strength of 0.15 J/m2 due to the inclusion of 33 wt.% glass fiber. Further addition of graphene in GE1 and GE2 led to notable improvements in hardness, reaching 68 and 74 Shore D, respectively. However, the impact strength displayed a decrease with the inclusion of graphene, with GE1 and GE2 showing values of 0.13 and 0.11 J/m2, respectively. When transitioning from pure epoxy (EP) to glass epoxy (GE), there is a 6.67% decrease in hardness, while the impact strength increases by 66.67%. Introducing 1 wt.% of graphene to the glass epoxy (GE1) results in a 21.43% increase in hardness but a 13.33% decrease in impact strength. Further adding 2 wt.% of graphene (GE2) leads to an additional 8.82% increase in hardness, though the impact strength decreases by 15.38%. X‐ray diffraction (XRD) analysis has revealed nano graphene presence and distribution, while fractography has revealed its effectiveness in enhancing interfacial adhesion and toughening mechanisms. Furthermore, XRD identifies potential changes in crystallinity or phase composition induced by nano graphene incorporation, further elucidating the composite's structure and properties. The study highlights the novel and significant trade‐offs encountered in optimizing the mechanical properties of epoxy‐based composites by incorporating graphene and glass fiber.

Thermal activation of kaolinite through potassium acetate intercalation: A structural and reactivity study

Calcined clays have emerged as a suitable alternative to partially replace conventional cement due to their high pozzolanic activity. This study explores a novel activation methodology for kaolinite, aiming to obtain metakaolin at lower temperatures than conventional thermal activation. This methodology involves a prior intercalation stage with potassium acetate (KAc) before thermal activation. The effectiveness of KAc intercalation was assessed through X-ray diffraction (XRD), indicating an intercalation ratio of approximately 90%. Several calcined temperatures were tested in accordance with the thermal behaviour analyzed through thermogravimetric analysis (TGA). Once calcined, the intercalated kaolinites exhibited enhanced reactivity compared to conventional calcined clays in the range between 400 °C to 550 °C, as demonstrated by modified Chapelle and Si/Al availability tests. A comprehensive structural characterization was conducted to facilitate a better understanding of the novel KAc-based metakaolin reactivity through various techniques (XRD, 27Al - 1H MAS NMR, and TGA). This focused on the crystalline changes in the kaolinite structure, the evolution of Al atoms conformation, and the OH behaviour at different thermal activation temperatures. Overall, this study highlights the potential of KAc intercalation as a strategy to obtain higher metakaolin content at lower temperatures than through conventional thermal treatments, offering insights into the development of its potential use as supplementary cementitious materials or alternative cementitious materials precursor.

A persistent mineralization process in alveolar bone throughout the postnatal growth stage in rats

ObjectiveAlveolar bone quality is essential for the maxillofacial integrity and function, and depends on alveolar bone mineralization. This study aims to investigate the in vivo changes in alveolar bone mineralization, from the perspective of mineral deposition and crystal transition in postnatal rats. DesignNine postnatal time points of Wistar rats, ranging from day 1 to 56, were set to obtain the maxillary alveolar bone samples. Each time point consisted of ninety rats, with 45 females and 45 males. Macromorphology of alveolar bone was reconducted by Micro-Computed Tomography and the mineral content was quantified via Thermogravimetric analysis, Scanning Electron Microscope, High-Resolution Transmission Electron Microscopy and vibrational spectroscopy. Furthermore, the crystallinity and composition were characterized by vibrational spectroscopy, X-ray Diffraction, X-ray Photoelectron Spectroscopy and Selected Area Electron Diffraction. ResultsThe progressive increase of mineral deposition was accompanied by substantial growth in alveolar bone mass and volume in postnatal rats. Whereas the mineral percentage initially decreased and then increased, reaching a nadir on postnatal day 14 (P14) when tooth eruption was first observed. Besides, localized mineralization was initiated by the formation of amorphous precursors and then converted into mineral crystals, while there was no statistically significant change in the average crystallinity of the bone during growth. ConclusionMineralization of alveolar bone is ongoing throughout the early growth in postnatal rats. Mineral deposition increases with age, whereas the crystallinity remains stable within a certain range. Besides, the mineral percentage reaches its lowest point on P14, which may be attributed to tooth eruption.

Corrosion study of glass coated high strength low alloy steel

In the present study, the glass slurry coating to a high-strength low-alloy steel (HSLA) substrate was investigated for corrosion resistance material. The crystallographic phases, degree of crystallinity, lattice parameters, and potential changes due to the coating process, and microstructural changes such as visual inspection of the surface, revealing thickness, uniformity, adhesion, potential defects, and elemental composition of the bare and coated steel were investigated by using the X-ray diffraction (XRD) and scanning electron microscopy and electron dispersive spectroscopy (SEM/EDS). The electrochemical behavior of the bare and coated steel samples was compared using potentiodynamic polarization and electrochemical impedance spectroscopy at various immersion periods in a 3.5 wt.% of sodium chloride (NaCl) solution. The higher corrosion resistance and lower corrosion rates of the coated steel surfaces were observed. The protection effectiveness of coatings is evaluated by examining their impedance and polarization characteristics. The effectiveness of the glass coatings in inhibiting corrosion is attributed to their role as a physical barrier and their ability to release corrosion inhibitors into the surrounding electrolyte. This information can be crucial for real-world applications requiring corrosion resistance.

Adsorption behavior and mechanism of tetracycline on microplastics subjected to peroxymonosulfate and alkaline aging

Microplastics (MPs) served as potential vectors for antibiotics in aquatic environments. The adsorption between MPs and antibiotics may be potentially affected by the aging processes for MPs. This study aimed to investigate the adsorption of tetracycline (TC) on polystyrene (PS), polypropylene (PP), polyethylene terephthalate (PET) and polylactic acid (PLA) aged by ferrous ion/peroxymonosulfate (Fe2+/PMS) and alkaline treatments. The results showed that both the physical and chemical properties of MPs experienced significant changes after aging. The surfaces of all four types of MPs became rougher, resulting in an increased specific surface area and a slight decrease in particle size. The O/C ratio was significantly increased after aging for PS and PP, which was changed slightly for PET and PLA. For PLA, the changes in crystallinity and hydrophobicity were different from the other three non-biodegradable MPs, with hydrophobicity enhancing after aging. The adsorption capacity of all four types of MPs for TC significantly increased after aging from the adsorption experiments. Particularly, after aging with Fe2+/PMS, the adsorption capacity of PET for TC increased to its highest value of 1.34 mg·g−1. Mechanism analysis indicated that the chemical adsorption of TC on MPs was mainly influenced by π-π interactions and hydrogen bonds.

Investigation of Stabilized Amorphous Solid Dispersions to Improve Oral Olaparib Absorption.

In this study, we investigated the formulation of stable solid dispersions to enhance the bioavailability of olaparib (OLA), a therapeutic agent for ovarian cancer and breast cancer characterized as a BCS class IV drug with low solubility and low permeability. Various polymers were screened based on solubility tests, and OLA-loaded solid dispersions were prepared using spray drying. The physicochemical properties of these dispersions were investigated via scanning electron microscopy (SEM), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and Fourier Transform Infrared Spectroscopy (FT-IR). Subsequent dissolution tests, along with assessments of morphological and crystallinity changes in aqueous solutions, led to the selection of a hypromellose (HPMC)-based OLA solid dispersion as the optimal formulation. HPMC was effective at maintaining the supersaturation of OLA in aqueous solutions and exhibited a stable amorphous state without recrystallization. In an in vivo study, this HPMC-based OLA solid dispersion significantly enhanced bioavailability, increasing AUC0-24 by 4.19-fold and Cmax by more than 10.68-fold compared to OLA drug powder (crystalline OLA). Our results highlight the effectiveness of HPMC-based solid dispersions in enhancing the oral bioavailability of OLA and suggest that they could be an effective tool for the development of oral drug formulations.

Experimental analysis of failure behaviour of PA12 specimens manufactured by SLS as a function of wall thickness and build direction

PurposeThis paper aims to investigate and explain the dual fracture behaviour of PA12 specimens sintered by selective laser sintering (SLS) as a function of wall thickness and build direction with a powder mixture 30:70. To achieve this objective, research related to chemical, thermal and structural behaviours as a function of the input variables was carried out to describe and explain why ductile-fragile behaviour occurs during fractures under uniaxial tension manufactured via a methodology of material analysis and manufacturing processes.Design/methodology/approachThe factorial design 32 relates the fracture of PA12 tensile specimens to the horizontal, transverse and vertical build directions at 2.0, 2.5 and 3.0 mm thicknesses, respectively. Fractographic images revealed the fracture surfaces and their dual ductile-fragile behaviour related to the specimens’ measured crystalline, thermal, surface and chemical properties.FindingsThe study showed that thermal property variables differ depending on the input variables. The wall thickness variable affected this morphology the most, showing the highest percentage of the ductile area, followed by the transverse and vertical directions. It was determined that the failure in the vertical direction is due to crystalline gradients associated with the layer-by-layer construction process. The pore density may be closely related to generating ductile and brittle areas.Originality/valueIn this paper, fracture characterisation is performed based on the mechanical, chemical, structural, thermal and morphological properties of PA12 manufactured by SLS. In addition, a heatmap of porosities in cross-sections is constructed using a machine learning model (k-means) related to dual fracture behaviour. This research revealed significant differences in the fracture type according to the build direction. In addition, thin-section fractography provides a more detailed explanation of the fragile behaviour of the vertical direction associated with crystalline changes due to the direction of the sintering layers.

Unveiling enhanced sound absorption in coconut wood through hemicellulose and lignin modification

Coconut wood (Cocos nucifera L.) is lightweight and has variable quality, making it a potential candidate for manufacturing sound absorption boards. However, its sound absorption coefficient needs enhancement to optimize its effectiveness in this application. This study aims to enhance its sound absorption properties using eco-friendly hydrogen peroxide and acetic acid treatments. This treatment modified the carbohydrate polymers (hemicellulose and cellulose) and lignin structures in the wood cell wall. The novelty of this approach lies in using these chemicals to improve acoustic performance significantly. Coconut wood samples were treated with a 1:1 acetic acid and hydrogen peroxide mixture for 20, 40, 60, and 80 min. Characterization techniques such as FTIR, XPS, and XRD, and 3D optical profilometry analyzed changes in chemical functionalities, crystallinity, and surface roughness. Sound absorption coefficients were measured using the impedance tube method. Results showed a significant improvement in sound absorption for all treated samples, especially at 60 min. The treatment also enhanced surface roughness, air permeability, porosity, and pore sizes, contributing to better sound absorption. This proposed treatment method addresses environmental consciousness and enhances the sustainable use and utilization of coconut wood.

Investigation of the link between first-order kinetic models of the in vitro digestion of native starches and the accompanying changes in their crystallinity and structure

Starch is the main source of dietary energy for humans. In order to understand the mechanisms governing native starch in vitro digestion, digestion data for six starches [wheat, maize, (waxy) maize, rice, potato and pea] of different botanical sources were fitted with the most common first-order kinetic models, i.e. the single, sequential, parallel and combined models. Parallel and combined models provided the most accurate fits and showed that all starches studied except potato starch followed a biphasic in vitro digestion pattern. The biological relevance of the kinetic parameters was explored by determining changes in crystallinity and molecular structure of the undigested starch residues during in vitro digestion. While the crystallinity of the undigested potato starch residues did not change substantially, a respectively small and large decrease in their amylose content and chain length during in vitro digestion was observed, indicating that amylose was digested slightly preferentially over amylopectin in native starch. However, the molecular structure of the starch residues changed too slowly and/or only to an insufficient extent to relate it to the kinetic parameters of the digested fractions predicted by the models. Such parameters thus need to be interpreted with caution, as their biological relevance still needs to be proven.

Cooperative In Situ Impregnation of PEG and Au Nanoparticles into Expanded CNT Network Toward Composite Phase Change Fibers with High Storage Capacity and Photothermal Conversion

AbstractPhase change fibers with multifunctionalities are a promising material for thermal management applications, however, it is still challenging to simultaneously give the fiber high energy conversion and storage capacity. Here, a cooperative in situ impregnation strategy is reported, to introduce Au nanoparticles (NPs) and polyethylene glycol (PEG) together into carbon nanotube (CNT) network during the expansion process, resulting in a CNT/Au/PEG composite phase change fiber. The obtained composite fiber have the characteristics of high loading (up to 88.0–98.6%) and uniform distribution of Au NPs, and thus exhibits superior mechanical, electrical, and thermal properties. The presence of Au NPs plays more important role in not only improving the PEG crystallinity and phase change enthalpy, but also enhancing the photothermal conversion efficiency (up to 88.2%). There is also a new feature of precise regulation of the phase change temperatures, e.g., from 9.5 to 20.5 °C for the solidification temperature. More importantly, due to the strong confinement of PEG and Au NPs inside the CNT network, the composite fiber also shows excellent thermal stabilities, including the anti‐leakage behavior and cycling phase change ability.

Structural changes in the crystalline lens as a function of the postmortem interval assessed with two-photon imaging microscopy.

The properties and structure of the crystalline lens change as time after death passes. Some experiments have suggested that these might be used to estimate the postmortem interval (PMI). In this study, the organization and texture of the rabbit lens were objectively evaluated as a function of the PMI using two-photon excitation fluorescence (TPEF) imaging microscopy. Between 24 h and 72 h, the lens presented a highly organized structure, although the fiber delineation was progressively vanishing. At 96 h, this turned into a homogeneous pattern where fibers were hardly observed. This behaviour was similar for parameters providing information on tissue texture. On the other hand, the fiber density of the lens is linearly reduced with the PMI. On average, density at 24 h was approximately two-fold when compared to 96 h after death. The present results show that TPEF microscopy combined with different quantitative tools can be used to objectively monitor temporal changes in the lens fiber organization after death. This might help to estimate the PMI, which is one of the most complex problems in forensic science.