Science and Technology of Advanced Materials最新文献

Catechol-containing polymers inspired by marine mussels have gained significant interest in recent years, leading to applications in several fields. Among these polymer systems, poly(vinylcatechol-styrene) (PVCS) has become a popular option due to its exceptional underwater adhesion strength, with readily available monomers and diverse synthetic routes being available. However, the translation of any novel adhesive chemistry from academic research to real-world applications can be challenging. Acrylates, epoxies, and urethanes were introduced to markets over half a century ago and remain dominant. However, bonding in wet environments remains lacking. The work presented here addresses this gap by focusing on the formulation of PVCS-based adhesives for conditions outside of the research lab. An emphasis was placed on handling properties when working underwater. A collection of different substrates were bonded together and several commercial glues provided benchmarks. Environmental conditions were studied to broaden the potential applications of PVCS adhesives in underwater settings. By optimizing formulations, we present an adhesive system that retains the superior underwater bonding of PVCS while also offering enhanced workability. This approach may help open the door to utilization of a new adhesive chemistry for underwater applications.

The concepts of bioinspiration and biomimetics that seek to elucidate the morphology and functions of living organisms and specific reactions within cells, and extraction of important elements from these concepts to design functional molecules and high-performance materials are becoming more and more widespread. This review summarizes the progress in research on hydrogels inspired by the stimuli-responsiveness of cell functions. For application to a self-regulated release system of insulin to regulate blood glucose levels, various polymer hydrogels have been designed using bioactive molecules such as enzymes and lectins to sense glucose concentrations. In addition, as a fully synthetic glucose-responsive hydrogel, a complex of a polymer having phenylboronic acid groups that form reversible bonds with sugars and a multivalent hydroxyl group polymer has been researched. This reversible hydrogel system can be further developed to act as an extracellular matrix in which cells can preferably reside. The proliferation and differentiation of encapsulated cells in hydrogels are controlled by reversible changes in the hydrogel properties in response to sugar. Another advantage is that cells can be safely retrieved by adding sugar to dissociate the hydrogel. These bioinspired polymer hydrogels can serve as important materials for the development of new medical technologies, such as the controlled release of bioactive molecules, regulated cell culture environmental matrices, and applications in layered and three-dimensional cell culture systems to create organized tissue structures.

The formation of copper oxide and zinc oxide mixture in montmorillonite was conducted by the reaction of an aqueous dispersion of Cu²⁺/Zn²⁺ exchanged montmorillonite and an aqueous solution of sodium hydroxide under hydrothermal treatment. The resulting product was characterized by X-ray diffraction, scanning and transmittance electron microscopies, as well as UV-visible and photoluminescence spectroscopies. The diffuse reflectance absorption spectra showed the absorption onsets due to copper oxide (885 nm) and zinc oxide (310 and 580 nm) in the product. The adsorption of methylene blue was fitted well by the Langmuir model with the maximum adsorption capacity of 454 mg⋅g^-1. The thermodynamic studies revealed that the process is exothermic and spontaneous. The photocatalytic activity of the hybrid was assessed by the degradation of methylene blue in aqueous solution under visible light irradiation. The most active species in the photocatalytic process was hydroxyl radicals. The regenerated copper oxide/zinc oxide-montmorillonite was reused up to 5 cycles, the photodegradation efficiency dropped only 5% (from 94% to 89%), supporting the good stability of the photocatalyst. The result was in agreement with the advantages of the nanocomposite heterostructure and the unique nature of montmorillonite.

Formaldehyde (FA) is a common pollutant found indoors and outdoors, posing a significant threat to human health. Therefore, developing sensitive and efficient detection methods for FA is essential for environmental monitoring and protecting public health. Herein, we report a naphthalimide-conjugated water-soluble polymeric fluorescent probe for the detection of FA in both aqueous and vapor phases using fluorimetric methods. The aromatic amines present in the side chain of the polymer react with FA, forming a Schiff base (imine bond). This imine formation inhibits the photoinduced electron transfer (PET) process within the polymer, leading to a 'turn-on' fluorescence under 365 nm UV light. The probe is capable of selectively sensing FA with a detection limit as low as 1.36 nM in aqueous medium. The formation of imine is confirmed for the model reaction between 6-(4-aminophenyl)-2-(4-((4-vinylbenzyl)oxy)phenyl)-1 h-benzo[de]isoquinoline-1,3(2 h)-dione and FA by electrospray ionization mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR) titration methods. The mechanism behind 'turn-on' FA sensing is investigated using density functional theory (DFT) analysis. Additionally, the study demonstrates a facile approach for covalently attaching the polymer on the surface of a filter paper surface via ultraviolet (UV) light-induced cross-linking. Such polymer attached paper exhibits FA vapor sensing through changes in fluorescence intensity.

In recent years, the development of next-generation secondary batteries employing resource-abundant metals such as Na has garnered significant attention. However, the high reactivity of Na raises safety concerns, necessitating the development of safer devices. To address this, ionic liquids (ILs) and organic ionic plastic crystals (OIPCs) have emerged as promising novel electrolytes. Despite their potential, studies investigating the influence of cation structures on various properties remain scarce, particularly in composites where Na salts are introduced into OIPCs. This study focuses on the effects of cation species and Na-salt concentration in OIPCs, specifically in N,N-diethylpyrrolidinium bis(fluorosulfonyl)amide ([C₂epyr][FSA]) and N-ethyl-N-isopropylpyrrolidinium bis(fluorosulfonyl)amide ([C_i3epyr][FSA]), with the addition of sodium bis(fluorosulfonyl)amide (NaFSA). The phase transition behavior, dissociation state of Na salts, and electrochemical properties exhibited significant differences based on the cationic structure of the OIPCs. The combination of each OIPC with Na salt resulted in liquid mixtures, and the ionic conductivity increased significantly as the Na salt concentration increased. High ionic conductivities were achieved with [C₂epyr][FSA]/NaFSA (20 mol%) and [C_i3epyr][FSA]/NaFSA (10 mol%), showing values of 2.7 × 10^-3 and 2.2 × 10^-3 S cm^-1 at 25°C, respectively. Linear sweep voltammetry results indicated superior oxidative stability in the [C_i3epyr][FSA] system. Solvation numbers of Na⁺, influenced by differences in cationic side-chain structures, were determined to be 2.7 for the [C₂epyr]⁺ system and 2.9 for the [C_i3epyr]⁺ system. The results suggest that controlling solvation numbers is a critical factor in the molecular design of high-performance ionic conductors.

Positron emission tomography (PET)/fluorescence dual-modal imaging combines deep penetration and high resolution, making it a promising approach for tumor diagnostics. Semiconductor nanocrystals, known as quantum dots (QDs), have garnered significant attention for fluorescence imaging owing to their tunable emission wavelength, high quantum yield, and excellent photostability. Among these QDs, heavy metal-free InP-based QDs have emerged as a promising candidate, addressing concerns regarding heavy metal-related toxicity. However, to the best of our knowledge, PET/fluorescence dual-modal imaging of InP QDs has yet to be explored. Here, we developed a novel PET/fluorescence imaging probe based on radioisotope (RI) -chelated InP/ZnSe/ZnS QDs for tumor imaging. The surface of the InP/ZnSe/ZnS QDs was functionalized with polyethylene glycol terminated with either a methoxy group or a 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelator group. Subsequently, the RI ⁶⁴Cu was chelated with DOTA on the surface of the InP/ZnSe/ZnS QDs, integrating their bright fluorescence with radioactivity. Using the obtained ⁶⁴Cu-chelated InP/ZnSe/ZnS QDs, PET/fluorescence dual-modal imaging of tumor-bearing mice was conducted, demonstrating successful multi-scale imaging from the whole body to the subcellular level. This novel PET/fluorescence dual-modal probe is expected to contribute to more precise tumor diagnosis.

This study delves into spin current-induced phenomena, such as spin-Hall magnetoresistance and the spin Seebeck effect within Pt films deposited on a noncollinear magnet, CoCr ${ }_2$ O ${ }_4$ (CCO), particularly at low temperatures. Detailed investigation of the angular dependencies of spin Hall magnetoresistance (SMR) and spin Seebeck effect (SSE) was carried out. The temperature-dependent behavior of both SMR and SSE signals exhibits a discernible variation correlated with different magnetic phases of CCO. To distinguish the contributions arising from magnetic proximity effects, we conducted X-ray magnetic dichroism (XMCD) at the Pt-M ${ }_3$ edge. XMCD data from Pt/CCO heterostructures suggest that any magnetic moment associated with Pt, if present, is below the detection limit. This supports the notion that the observed signals primarily stem from SMR and SSE. This study offers insights into spin-current-driven phenomena, paving the way for potential spintronic applications.

Catalysts' redox reactions are crucial for storage and energy conversion. Therefore, the fabrication of cost-effective, structurally rational, and multifunctional advanced catalytic materials continues to be a crucial task. In this study, we obtained P, Fe, and Co co-doped, nitrogen-rich carbon nanofibers by directly forming carbon nanotubes from metal-organic frameworks through electrospinning and pyrolysis. The P_0.025-FeCo/C catalyst demonstrated outstanding ORR activity, including an ECSA of 1954.3 cm², a limited current density of -3.98 mA/cm², an E_1/2 of ~0.84 V, and an E_onset of ~0.94 V. After 5000 cycles, the P_0.025-FeCo/C catalyst demonstrated remarkable enduring stability. These function enhancements occurred because of the electronic coupling between the metal and phosphorus, which altered the electron distribution at the metal center and optimized its electronic structure, thereby improving catalytic activity and stability. It exhibits good chemical stability in alkaline media and can maintain its catalytic performance for a long time, demonstrating good durability. Its tubular structure provides many active sites and superior electron transport paths owing to its unique channels and cavities, which help improve its activity and stability. Therefore, P_0.025-FeCo/C is expected to become a non-precious metal catalyst for facilitating oxygen reduction reactions.

This study proposes a novel mechanism of intergranular fracture in alpha-iron, focusing on the effects of trapped vacancies, H atoms, and their synergistic interplay under tensile strain. We present a methodology for the introduction of H into grain boundaries (GBs) resulting in a realistic distribution by considering H-H interactions. Accordingly, optimal H concentrations were determined under specific environmental conditions for GBs with and without vacancy-induced segregation under zero and 2% tensile strain, respectively. Subsequently, the reduction in cohesive energy at GBs was evaluated at the optimal H concentration under these conditions. In the case of H segregation without vacancies at zero applied strain, the reduction in the cohesive energy ranged approximately from 15% to 35% for all the GB configurations. Eventually, vacancy segregation increased H concentration at the GBs, defined as vacancy-induced H segregation. The vacancy-induced H segregation resulted in a 60-117% increase in H concentration and a 70-80% decrease in cohesive energy at a vacancy concentration of $7.49\hspace{0.17em}1/n{m}^2$ under zero applied strain. The proposed vacancy-induced H-segregation mechanism explained the delayed fracture in steel. Furthermore, the effect of tensile strain on embrittlement was elucidated, with strain-induced vacancy redistribution and vacancy-induced H segregation synergistically promoting GB decohesion, resulting in a 73-93% reduction in cohesive energy at the same vacancy concentration.