Nanomaterials最新文献

This study presents a novel approach to the development of high-performance supercapacitors through 3D printing technology. We synthesized a composite material consisting of silver-doped reduced graphene oxide (rGO) and dodecylbenzenesulfonic acid (DBSA)-doped polyaniline (PANI), which was further blended with polylactic acid (PLA) for additive manufacturing. The composite was extruded into filaments and printed into circular disc electrodes using fused deposition modeling (FDM). These electrodes were assembled into symmetric supercapacitor devices with a solid-state electrolyte. Electrochemical characterization, including cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) tests, demonstrated considerable mass-specific capacitance values of 136.2 F/g and 133 F/g at 20 mV/s and 1 A/g, respectively. The devices showed excellent stability, retaining 91% of their initial capacitance after 5000 cycles. The incorporation of silver nanoparticles enhanced the conductivity of rGO, while PANI-DBSA improved electrochemical stability and performance. This study highlights the potential of combining advanced materials with 3D printing to optimize energy storage devices, offering a significant advancement over traditional manufacturing methods.

Bacterial nanocellulose (BNC) is considered a promising alternative to microcrystalline cellulose, as well as an ingredient in low-calorie dietary products. However, the risks of BNC when consumed with food are not well characterized. The aim of this study is to investigate the impact of BNC on immune function, the intestinal microbiome, intestinal barrier integrity, and allergic sensitization in subacute experiments on rats. Male Wistar rats received BNC with a diet for eight weeks in a dose range of 1-100 mg/kg of body weight. The measurements of serum levels of cytokines, adipokines, iFABP2, indicators of cellular immunity, composition of the intestinal microbiome, and a histological study of the ileal mucosa were performed. In a separate four-week experiment on a model of systemic anaphylaxis to food antigen, BNC at a dose of 100 mg/kg of body weight did not increase the severity of the reaction or change the response of IgG antibodies. Based on dose-response effects on immune function, the non-observed adverse effect level for BNC was less than 100 mg/kg of body weight per day. The effects of BNC on the gut microbiome and the intestinal mucosal barrier were not dose-dependent. Data on the possible presence of prebiotic effects in BNC have been obtained.

Herein, silicon nitride (Si₃N₄) was the selected additive to be examined for its reinforcing properties on high-density polyethylene (HDPE) by exploiting techniques of the popular material extrusion (MEX) 3D printing method. Six different HDPE/Si₃N₄ composites with filler percentages ranging between 0.0-10.0 wt. %, having a 2.0 step, were produced initially in compounds, then in filaments, and later in the form of specimens, to be examined by a series of tests. Thermal, rheological, mechanical, structural, and morphological analyses were also performed. For comprehensive mechanical characterization, tensile, flexural, microhardness (M-H), and Charpy impacts were included. Scanning electron microscopy (SME) was used for morphological assessments and microcomputed tomography (μ-CT). Raman spectroscopy was conducted, and the elemental composition was assessed using energy-dispersive spectroscopy (EDS). The HDPE/Si₃N₄ composite with 6.0 wt. % was the one with an enhancing performance higher than the rest of the composites, in the majority of the mechanical metrics (more than 20% in the tensile and flexural experiment), showing a strong potential for Si₃N₄ as a reinforcement additive in 3D printing. This method can be easily industrialized by further exploiting the MEX 3D printing method.

Although the irreplaceable position of silicon (Si) semiconductor materials in the field of information has become a consensus, new materials continue to be sought to expand the application range of semiconductor devices. Among them, research on wide bandgap semiconductors has already achieved preliminary success, and the relevant achievements have been applied in the fields of energy conversion, display, and storage. However, similar to the history of Si, the immature material grown and device manufacturing processes at the current stage seriously hinder the popularization of wide bandgap semiconductor-based applications, and one of the crucial issues behind this is the defect problem. Here, we take amorphous indium gallium zinc oxide (a-IGZO) and 4H silicon carbide (4H-SiC) as two representatives to discuss physical/mechanical properties, electrical performance, and stability from the perspective of defects. Relevant experimental and theoretical works on defect formation, evolution, and annihilation are summarized, and the impacts on carrier transport behaviors are highlighted. State-of-the-art applications using the two materials are also briefly reviewed. This review aims to assist researchers in elucidating the complex impacts of defects on electrical behaviors of wide bandgap semiconductors, enabling them to make judgments on potential defect issues that may arise in their own processes. It aims to contribute to the effort of using various post-treatment methods to control defect behaviors and achieve the desired material and device performance.

Autophagy leads to cellular tolerance of the therapeutic pressure of chemotherapeutic drugs, resulting in treatment resistance. Therefore, the effective monitoring of the autophagy status of tumors in vivo and the regulating of the autophagy level are crucial for improving the efficacy of chemotherapy. In this work, we grafted nitroxide radicals onto the surface of iron oxide nanoparticles (Fe₃O₄ NPs) using dendrimer polymers, yielding Fe₃O₄-NO· NPs that are responsive to reactive oxygen species (ROS) and possess enhanced T1 and T2 signal capabilities in a magnetic resonance imaging (MRI) measurement. The ROS in tumor cells generated by autophagy quenches the nitroxide radicals, thereby weakening the T1 signal. In contrast, Fe₃O₄ NPs are unaffected by intracellular ROS, leading to a stable T2 signal. By comparing the intensity ratio of T1 to T2 in Fe₃O₄-NO· NPs, we can evaluate the in vivo autophagy status within tumors in real time. It also revealed that Fe₃O₄-NO· NPs loaded with doxorubicin (Dox) and combining the autophagy inhibitor exhibited high antitumor activity in cells and tumor-bearing mice. This system, which combines real-time monitoring of tumor cell autophagy with the delivery of chemotherapeutic drugs, provides an innovative and effective strategy for tumor treatment with potential clinical application prospects.

We report the pulsed laser deposition (PLD) of nanocrystalline/amorphous homo-composite BaTiO₃ (BTO) films exhibiting an unprecedented combination of a colossal dielectric constant (ε_r) and extremely low dielectric loss (tan δ). By varying the substrate deposition temperature (T_d) over a wide range (300-800 °C), we identified T_d = 550 °C as the optimal temperature for growing BTO films with an ε_r as high as ~3060 and a tan δ as low as 0.04 (at 20 kHz). High-resolution transmission electron microscopy revealed that the PLD-BTO films consist of BTO nanocrystals (~20-30 nm size) embedded within an otherwise amorphous BTO matrix. The impressive dielectric behavior is attributed to the combination of highly crystallized small BTO nanograins, which amplify interfacial polarization, and the surrounding amorphous matrix, which effectively isolates the nanograins from charge carrier transport. Our findings could facilitate the development of next-generation integrated dielectric devices.

The increasing concentration of CO₂ in the atmosphere is one of the main factors contributing to global climate change [...].

Rare-earth-metal-based materials have emerged as frontrunners in the quest for high-performance hydrogen storage solutions, offering a paradigm shift in clean energy technologies. This comprehensive review delves into the cutting-edge advancements, challenges, and future prospects of these materials, providing a roadmap for their development and implementation. By elucidating the fundamental principles, synthesis methods, characterization techniques, and performance enhancement strategies, we unveil the immense potential of rare-earth metals in revolutionizing hydrogen storage. The unique electronic structure and hydrogen affinity of these elements enable diverse storage mechanisms, including chemisorption, physisorption, and hydride formation. Through rational design, nanostructuring, surface modification, and catalytic doping, the hydrogen storage capacity, kinetics, and thermodynamics of rare-earth-metal-based materials can be significantly enhanced. However, challenges such as cost, scalability, and long-term stability need to be addressed for their widespread adoption. This review not only presents a critical analysis of the state-of-the-art but also highlights the opportunities for multidisciplinary research and innovation. By harnessing the synergies between materials science, nanotechnology, and computational modeling, rare-earth-metal-based hydrogen storage materials are poised to accelerate the transition towards a sustainable hydrogen economy, ushering in a new era of clean energy solutions.

In this work, the nonlinear optical (NLO) properties of CuO nanoparticles (CuO NPs) were studied experimentally using the pulsed laser ablation (PLA) technique. A nanosecond Nd: YAG laser was employed as the ablation excitation source to create CuO NPs in distilled water. Various CuO NPs samples were prepared at ablation periods of 20, 30, and 40 min. Utilizing HR-TEM, the structure of the synthesized CuO NPs samples was verified. In addition, a UV-VIS spectrophotometer was used to investigate the linear features of the samples. The Z-scan technique was utilized to explore the NLO properties of CuO NPs samples, including the nonlinear absorption coefficient (β) and nonlinear refractive index (n2). An experimental study on the NLO features was conducted at a variety of excitation wavelengths (750-850 nm), average excitation powers (0.8-1.2 W), and CuO NPs sample concentrations and sizes. The reverse saturable absorption (RSA) behavior of all CuO NPs samples differed with the excitation wavelength and average excitation power. In addition, the CuO NPs samples demonstrated excellent optical limiters at various excitation wavelengths, with limitations dependent on the size and concentration of CuO NPs.

The influence of Eu doping (0.5, 1 and 2 mol.%) and annealing in an oxygen-deficient atmosphere on the structure and optical properties of SnO₂ nanoparticles were investigated in relation to electronic structure. The X-ray diffraction (XRD) patterns revealed single-phase tetragonal rutile structure for both synthesized and annealed Eu-doped SnO₂ samples, except for the annealed sample with 2 mol.% Eu. The results of X-ray photoelectron spectroscopy (XPS) emphasized that europium incorporated into the SnO₂ host lattice with an oxidation state of 3+, which was accompanied by the formation of oxygen vacancies under cation substitution of tetravalent Sn. Moreover, XPS spectra showed the O/Sn ratio, which has been reduced under annealing for creating additional oxygen vacancies. The pulse cathodoluminescence (PCL) demonstrated the concentration dependence of Eu site symmetry. Combination of XRD, XPS and PCL revealed that Eu doping and following annealing induce strongly disordering of the SnO₂ crystal lattice. Our findings provide new insight into the interaction of rare-earth metals (Eu) with host SnO₂ matrix and new evidence for the importance of oxygen vacancies for optical and electronic structure formation.