Materials Horizons最新文献

Flexible hydrogel sensors have found extensive applications. However, the insufficient sensing sensitivity and the propensity to freeze at low temperatures restrict their use, particularly in frigid conditions. Herein, a multifunctional eutectogel with high transparency, anti-freezing, anti-swelling, adhesive, and self-healing properties is prepared by a one-step photopolymerization of acrylic acid and lauryl methacrylate in a binary solvent comprising water and deep eutectic solvent (DES). The results from the molecular dynamics simulations and density functional theory indicate that the hydrogen bonds between DES and water mixtures possess better stability than those between water molecules. On the other hand, DES breaks down hydrogen bonds in water, providing eutectogels with excellent anti-freezing even at -60 °C. Cetyltrimethylammonium bromide is incorporated to establish stable hydrophobic interactions and electrostatic attractions with polymer chains in the eutectogel network, resulting in superior mechanical (elongation at break of 2890%) and anti-swelling (only 2% swelling in water over 7 days) properties. The eutectogel-based strain sensors exhibit remarkable sensitivity, achieving a gauge factor of up to 15.4. The multifunctional eutectogel sensors can monitor motion and transmit encrypted information at low temperatures, demonstrating considerable potential for applications in flexible electronics within low-temperature environments.

Silver-based fast ionic conductors show promising potential in thermoelectric applications. Among these, Ag₂S offers unique high plasticity but low electrical conductivity, whereas Ag₂Te exhibits high intrinsic electrical conductivity yet faces limitations due to high thermal conductivity and poor plasticity. Developing a composite thermoelectric material that combines the benefits of both is therefore essential. Here, this study reports the successful synthesis of Ag₂Te/Ag₂S composites via a facile and low-cost solvothermal method. By finely adjusting the composition of Ag₂S and Ag₂Te to obtain the optimized carrier concentration and the enhanced mobility, the figure of merit ZT of Ag₂Te/Ag₂S composites reached ∼0.42 at 373 K and ∼0.38 at 298 K, both surpassing those of pure Ag₂S and Ag₂Te. This increase in ZT also benefits from lattice defects created by the solvothermally synthesized biphasic composition, effectively scattering phonons of various wavelengths and reducing thermal conductivity compared to pure Ag₂Te. Additionally, the plasticity of the Ag₂Te/Ag₂S composites improved considerably over pure Ag₂Te, achieving a bending strain of ∼2.5% (versus ∼1.2% for intrinsic Ag₂Te). This study can fill a critical gap in the research on composite silver-based fast ionic conductors synthesized via wet chemical methods and provide valuable guidance for future exploration.

The semi-hydrogenation of alkynes into alkenes rather than alkanes is of great importance in the chemical industry, and palladium-based metallic catalysts are currently employed. Unfortunately, a fairly high cost and uncontrollable over-hydrogenation impeded the application of Pd-based catalysts on a large scale. Herein, a sandwich structure single atom Pd catalyst, Z@Pd@Z, was prepared via impregnation exchange and epitaxial growth methods (Z stands for ZIF-8), in which Pd single atoms were stabilized by pyrrolic N in a zeolitic imidazolate framework (ZIF-8). Semi-hydrogenation of acetylene was performed and Z@Pd@Z achieved 100% acetylene conversion at 120 °C with an ethylene selectivity of more than 98.3% at an extra low Pd concentration. Z@Pd@Z exhibited a specific activity of 1872.69 mL_C2H4 mg_Pd^-1 h^-1, surpassing most of the reported Pd-based catalysts. The existence of Pd single atoms coordinated by nitrogen (Pd-N₄) was verified by XAS (synchrotron X-ray absorption spectroscopy), which provided active sites for H₂ dissociation and the dissociated hydrogen quickly spilled over the surface of the outer ZIF layer to hydrogenate alkyne to ethene; besides, the catalytic activity could be controlled by adjusting the thickness of the outer ZIF layer. The confinement of the ZIF on Pd single-atom sites and the high energy barrier of ethylene hydrogenation were found to be responsible for the superior C₂H₂ semi-hydrogenation activity. This work opens up valuable insights into the design of ZIF-derived single-atom catalysts for efficient acetylene selective hydrogenation.

In such an era of information explosion, improving the level of information security is still a challenging task. Self-erasing luminescent hydrogels are becoming ideal candidates for improving the level of information security with simple encryption and decryption methods. Herein, a lanthanide-polyoxometalate-based self-erasing luminescent hydrogel with time-dependent and resilient properties was constructed through a covalent crosslinked network constructed with polyacrylamide and a non-covalent crosslinked network constructed with [2-(methacryloyloxy)ethyl]trimethyl ammonium chloride/Na₉DyW₁₀O₃₆, along with doping urease. This acquired hydrogel exhibited reversible luminescence switching properties in the presence of HCl-urea mixed solution. At the same time, obvious changes in the luminescence intensity can be seen on the timescale by modulating the concentrations of HCl and urea/urease. Based on this, the information loaded onto the hydrogel by using a HCl-urea mixed solution self-erased over time, leading to misinformation during this process. The real information can only be recognized at a specific time. Moreover, the information is self-erased permanently, which can avoid secondary leakage of information. In addition, the hydrogel has excellent resilience. The information can be loaded in the stretched state of the hydrogel, resulting in the information only being recognized in the re-stretched state of the hydrogel while the information cannot be recognized in the normal state of the hydrogel. The combination of time-dependent and resilient properties of the hydrogel can further improve the level of information security effectively. This self-erasing luminescent hydrogel with time-dependent and resilient properties has great potential in improving the security of information encryption.

Organ-on-a-chip (OoC) is a breakthrough technology in biomedicine. As microphysiological systems constructed in vitro, OoCs can simulate the main structures and functions of human organs, thereby providing a powerful tool for drug screening and disease model construction. Furthermore, the coupling of OoCs and sensors has been an innovative discovery in the field of biomedical and electronic engineering in recent years. The integration of sensors into OoCs allows the real-time monitoring of the changes in the microenvironmental parameters within the chip, reflecting the physiological responses of cells or tissues in the OoC and providing more accurate data support for drug development and disease treatment. In this work, we briefly outline the design ideas of OoCs, summarize the commonly used materials for OoCs and their advantages and disadvantages, and provide the most recent practical examples of the combination of OoCs and sensors in pharmaceutical and medical sciences. Furthermore, perspectives, challenges and their solutions in the future development of this technology are provided, with the aim to inspire the researchers to work toward the subsequent development of OoCs having improved reliability.

Linearly-polarized organic electroluminescent devices have gained significant attention due to their potential applications across various fields. However, traditional thin-film organic light-emitting diodes (OLEDs) face significant challenges, primarily due to the necessity of incorporating complex optical elements. In this study, we present linearly-polarized OLEDs (LP-OLEDs) based on organic single crystals that we have designed and prepared. These devices exhibit a degree of polarization (DOP) of up to 0.96 for photoluminescence and 0.95 for electroluminescence, values that are close to the ideal linearly-polarized light (DOP = 1). The LP-OLEDs demonstrate outstanding performance, with a low turn-on voltage of just 2.5 volts, an exceptionally high brightness of 200 000 cd m^-2, and a current density surpassing 300 A cm^-2. This is the best overall performance reported for single crystal-based OLEDs to date. These results open the door to the development of next-generation, low-power consumption displays, marking a significant step forward in the field of organic single crystal-based LP-OLEDs.

The porous polymer is a common and fascinating category within the vast family of porous materials. It offers valuable features such as sufficient raw materials, easy processability, controllable pore structures, and adjustable surface functionality by combining the inherent properties of both porous structures and polymers. These characteristics make it an effective choice for designing functional and advanced materials. In this review, the structural features, processing techniques and application fields of the porous polymer are discussed comprehensively to present their current status and provide a valuable tutorial guide and help for researchers. Firstly, the basic classification and structural features of porous polymers are elaborated upon to provide a comprehensive analysis from a mesoscopic to macroscopic perspective. Secondly, several established techniques for fabricating porous polymers are introduced, including their respective basic principles, characteristics of the resulting pores, and applied scopes. Thirdly, we demonstrate application research of porous polymers in various emerging frontier fields from multiple perspectives, including pressure sensing, thermal control, electromagnetic shielding, acoustic reduction, air purification, water treatment, health management, and so on. Finally, the review explores future directions for porous polymers and evaluates their future challenges and opportunities.

Bionic evaporators inspired by natural plants like bamboo and mushrooms have emerged as efficient generators through water capillary evaporation. However, primitive natural evaporators cannot currently meet growing demand, and their performance limitations remain largely unexplored, presenting a substantial challenge. Through extensive experimentation and detailed simulation analysis, this study presents a precisely engineered H-type bamboo steam generator. This innovative design incorporates a unique node structure embedded with graphite flakes and an internode characterized by micro- and nanoporous channels, all achieved through streamlined carbonization. The results are striking: a water evaporation rate of 2.28 kg m^-2 h^-1 and a photothermal conversion efficiency of 90.2% under one-sun irradiation, outperforming comparable alternatives. This study also marks the first comprehensive simulation in COMSOL modeling water capillary evaporation, driven by the synergistic effects of photothermal graphitic layers, broad-spectrum solar absorption, and capillary microstructures. The chimney-assisted, enclosed cavity structure further enhances water capillary evaporation and thermal localization. This breakthrough not only enables efficient use of waste biomass but also advances the field of sustainable materials, opening new avenues in solar-driven steam generation.

While reversible information encryption and decryption are readily achievable with hydrogels, this process presents a significant challenge when applied to elastic polymer films. This is due to the inherent chemical stability of anhydrous polymer films which significantly increases the difficulty of information writing. In this study, we propose a solvent-free radical polymerization method for chemical patterning on the elastic film of poly(styrene-butadiene-styrene) (SBS). Unlike short chain crosslinkers-induced patterning, which increases the brittleness of the film, the long-chain crosslinkers are chemically bonded with the chains of SBS. This not only enhances the mechanical stability of film, but also improves its softness and robustness (the strength increases 1.8 times and the toughness increases 2.3 times), thereby greatly extending its durability for information encryption and decryption. When patterned with a photomask, the crosslinked regions maintain transparency upon acetone absorption, while the non-crosslinked regions become opaque due to an acetone-induced phase change. Upon removal of acetone, these opaque regions can be restored to transparency. Compared with hydrogels liable to water loss and deformation, the patterned films show greater stability, retaining pattern encryption/decryption functions after 30 days in a natural environment without special storage. The rate of this phase transition is directly related to the degree of crosslinking. Therefore, by adjusting the degree of crosslinking, the patterned films can undergo multistage encryption/decryption in response to acetone, providing a promising method for information security and storage.

The stable operation of high-capacity lithium-sulfur batteries (LSBs) has been hampered by slow conversion kinetics of lithium polysulfides (LiPSs) and instability of the lithium metal anodes. Herein, 6-(dibutylamino)-1,3,5-triazine-2,4-thiol (DTD) is introduced as a functional additive for accelerating the kinetics of cathodic conversion and modulating the anode interface. We proposed that a coordination interaction mechanism drives the polysulfide conversion and modulates the Li⁺ solvated structure during the binding of the N-active site of DTD to LiPSs and lithium salts. The results show that DTD effectively promotes the redox of LiPSs and the formation of an inorganic-organic synergistic solid electrolyte interface (SEI). This suppresses the parasitic reaction of LiPSs and confers uniform lithium deposition. Therefore, the capacity decay rate per cycle of the DTD-added LSBs is only 0.066% after 600 cycles at 1C. Moreover, Li-Li symmetric batteries exhibited smaller overpotentials during long cycling and a 41% increment in cycle life. Even with high sulfur loading (5.38 mg cm^-2) and a depleted electrolyte sulfur ratio (E/S = 5 μL mg^-1), the capacity retention of the battery is 71.5%. This work provides a new reference for elucidating the mechanisms of polysulfide conversion and SEI interface regulation for high-energy-density lithium-sulfur batteries.