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MXene nanosheets are considered advantageous for functional materials, but current delamination methods to prepare MXene nanosheets have many limitations including high cost, small production scale, low efficiency, and deteriorated structure integrity of obtained nanosheets. Here, we propose a simple, efficient, and scalable shear stress-induced delamination (SSID) strategy to boost the production of single-/few-layered Ti3C2Tx MXene nanosheets. Molecular dynamics simulation indicates that the pan mill-type grinding discs create a strong hydrodynamic flow field, which exerts gigantic shear stress to substantially delaminate the multilayered MXene stacks into homogeneously dispersed MXene nanosheets. Furthermore, shear stress generated from vigorous water flow has limited fragmentation effect, ensuring large lateral size and good structure integrity to the obtained MXene nanosheets as evidenced by the morphological and structural characterizations. Compared to conventional delamination methods, this novel SSID strategy exhibits great advantages in terms of efficiency, scalability and the properties of resultant MXene nanosheets, which opens up great opportunity for the scalable production and commercialization of high-performance MXene-based materials.

As a layered material with single/multi-atom thickness, two-dimensional transition metal sulfide WS2 has attracted extensive attention in the field of science for its excellent physical, chemical, optical, and electrical properties. The photoelectric properties of WS2 are even more promising than graphene. However, there are many existing preparation methods for WS2, but few reports on its direct growth on tungsten films. Therefore, this paper studies its preparation method and proposes an innovative two-dimensional material preparation method to grow large-sized WS2 with higher quality on metal film. In this experiment, it was found that the reaction temperature could regulate the growth direction of WS2. When the temperature was below 950 °C, the film showed horizontal growth, while when the temperature was above 1000 °C, the film showed vertical growth. At the same time, through Raman and band gap measurements, it is found that the different thicknesses of precursor film will lead to a difference in the number of layers of WS2. The number of layers of WS2 can be controlled by adjusting the thickness of the precursor.

WTe2 has attracted much attention because of its layered structure and special electronic energy band structure. However, due to the difficulty of evaporating the W element itself and the inactivity of the Te element, the obtained large-area WTe2 thin films are usually accompanied by many defects. In this paper, WTe2 nanocrystalline films were successfully prepared on quartz substrates using magnetron sputtering and chemical vapor deposition techniques. Various analytical techniques such as X-ray Diffraction, Raman spectra, X-ray Photoelectron Spectroscopy, Scanning Electron Microscope, and photoluminescence spectra are employed to analyze the crystal structure, composition, and morphology. The effects of different tellurization temperatures and tellurization times on the properties of WTe2 thin films were investigated. WTe2 nanocrystalline films with good crystallinity were obtained at 600 °C for 30 min. The thermal conductivity of the WTe2 films prepared under this condition was 1.173 Wm−1K−1 at 300 K, which is significantly higher than that of samples prepared using other methods.

Composite films containing different amounts of potassium sorbate (KS) were prepared by using fish scale collagen (Col) and polyvinyl alcohol (PVA). Fourier transform infrared spectroscopy (FTIR), light transmittance, mechanical, water vapor transmission rate (WVTR), and the antibacterial properties of the composite films were analyzed. The results showed that the addition of Col significantly reduced the light transmittance of the composite film, but KS had no significant effect on the light transmission. The tensile strength decreased first and then increased with the addition of KS, while the WVTR increased first and then decreased. The composite film exhibited a certain degree of antibacterial properties against E. coli and S. aureus. In addition, we found that ultrasonic treatment reduced the WVTR, and also improved tensile strength and elongation at break of the composite films, but had no significant effect on other properties. The KS/Col/PVA films have the potential to be used as antimicrobial food packaging.

As a layered material with single/multi-atom thickness, two-dimensional transition metal sulfide WS2 has attracted extensive attention in the field of science for its excellent physical, chemical, optical, and electrical properties. The photoelectric properties of WS2 are even more promising than graphene. However, there are many existing preparation methods for WS2, but few reports on its direct growth on tungsten films. Therefore, this paper studies its preparation method and proposes an innovative two-dimensional material preparation method to grow large-sized WS2 with higher quality on metal film. In this experiment, it was found that the reaction temperature could regulate the growth direction of WS2. When the temperature was below 950 °C, the film showed horizontal growth, while when the temperature was above 1000 °C, the film showed vertical growth. At the same time, through Raman and band gap measurements, it is found that the different thicknesses of precursor film will lead to a difference in the number of layers of WS2. The number of layers of WS2 can be controlled by adjusting the thickness of the precursor. [ABSTRACT FROM AUTHOR]

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WTe2 has attracted much attention because of its layered structure and special electronic energy band structure. However, due to the difficulty of evaporating the W element itself and the inactivity of the Te element, the obtained large-area WTe2 thin films are usually accompanied by many defects. In this paper, WTe2 nanocrystalline films were successfully prepared on quartz substrates using magnetron sputtering and chemical vapor deposition techniques. Various analytical techniques such as X-ray Diffraction, Raman spectra, X-ray Photoelectron Spectroscopy, Scanning Electron Microscope, and photoluminescence spectra are employed to analyze the crystal structure, composition, and morphology. The effects of different tellurization temperatures and tellurization times on the properties of WTe2 thin films were investigated. WTe2 nanocrystalline films with good crystallinity were obtained at 600 °C for 30 min. The thermal conductivity of the WTe2 films prepared under this condition was 1.173 Wm−1K−1 at 300 K, which is significantly higher than that of samples prepared using other methods. [ABSTRACT FROM AUTHOR]

Electromagnetic interference pollution has raised urgent demand for the development of electromagnetic interference shielding materials. Transition metal carbides (MXenes) with excellent conductivity have shown great potential in electromagnetic interference (EMI) shielding materials, while the poor mechanical strength, flexibility, and structural stability greatly limit their further applications. Here, cellulose nanofibers and sodium alginate are incorporated with MXene nanosheets as flexible matrices to construct strong and flexible mussel-like layered MXene/Cellulose nanofiber/Sodium Alginate composite films, and nickel ions are further introduced to induce metal coordination crosslinking of alginate units. Benefited from the dual-crosslinked network structure of hydrogen bonding and metal coordination, the tensile strength, Young's modulus, and toughness of the MXene/cellulose nanofiber/nickel alginate composite film are significantly increased. After subsequent reduction by ascorbic acid, excess nickel ions are reduced to nickel nanoparticles and uniformly dispersed within the highly conductive composite film, which further improved its hysteresis loss effect toward the incident electromagnetic waves. Consequently, the MXene/cellulose nanofiber/nickel alginate-Ni composite film presents a considerably enhanced electromagnetic interference shielding effectiveness (47.17 dB) at a very low thickness of 29 µm. This study proposes a feasible dual-crosslinking and subsequent reduction strategy to synergistically enhance the mechanical properties and electromagnetic interference shielding performance of MXene-based composite materials. [ABSTRACT FROM AUTHOR]

Construction of sustainable composite biofilms from natural biopolymers are greatly promising for advanced packaging applications due to their biodegradable, biocompatible, and renewable properties. In this work, sustainable advanced food packaging films are developed by incorporating lignin nanoparticles (LNPs) as green nanofillers to starch films. This seamless combination of bio-nanofiller with biopolymer matrix is enabled by the uniform size of nanofillers and the strong interfacial hydrogen bonding. As a result, the as-prepared biocomposites exhibit enhanced mechanical properties, thermal stability, and antioxidant activity. Moreover, they also present outstanding ultraviolet (UV) irradiation shielding performance. As a proof of concept in the application of food packaging, we evaluate the effect of composite films on delaying oxidative deterioration of soybean oil. The results indicate our composite film could significantly decrease peroxide value (POV), saponification value (SV), and acid value (AV) to delay oxidation of soybean oil during storage. Overall, this work provides a simple and effective method for the preparation of starch-based films with enhanced antioxidant and barrier properties for advanced food packaging applications. [ABSTRACT FROM AUTHOR]

This study is about the influence of magnesium oxide (MgO) and zinc oxide (ZnO) nanoparticles on the morphology, structural, thermal and mechanical properties of the polylactic acid (PLA) films. The pure PLA and PLA nanocomposites were prepared using a cost-effective film applicator at 2 and 5 wt% of nanofillers. The dispersity and elements were examined by scanning electron microscopy with energy dispersive spectroscopy. For 2 wt% of nanofiller in the film, the agglomeration of nanoparticles was not observed, whereas for higher weight percentages agglomeration took place. X-ray diffraction study confirms the improved crystallinity of PLA at 2 wt% nanofillers. Thermal analysis of PLA composite films confirms that the values of glass transition (Tg), crystallization (Tc) and melting temperature (Tm) increased for 2 wt% and decreased for 5 wt% nanofillers. At 2 wt%, the glass transition temperatures of PLA/ZnO and PLA/MgO nanocomposite films are 63 and 62°C, respectively. Further, the tensile test confirms that 2 wt% of nanofiller-incorporated PLA films have better properties than 5 wt% of nanofiller due to the better dispersion of nanoparticles. At 2 wt% of MgO and ZnO nanoparticles, tensile strength (Ts) was increased to 19.4 ± 0.97 and 22 ± 1.1 MPa, respectively. The prepared PLA nanocomposite films with improved thermal and mechanical properties can be utilized in food packaging applications. [ABSTRACT FROM AUTHOR]

Redox‐active metal–organic frameworks (MOFs), with switchable physicochemical properties depending on their redox state, are widely used in catalysis, selective separation, and electrochemical sensing. However, the complex fabrication process limits the applications. Herein, a post‐synthetic modification strategy is proposed to prepare redox‐active MOFs by covalent grafting organic selenium compounds. The selenium moieties can reduce metal salt to in situ generate metal nanoparticles (MNPs) without an external reducing agent, and also act as anchors to stabilize the generated MNPs. As a proof of concept, two kinds of MOFs are selected to prepare redox‐active MOFs‐Se and further fabricate MNPs@MOFs composite materials. With controllable confinement of the MNPs, the MNPs@MOFs composite show noteworthy photocatalytic and electrocatalytic activity. [ABSTRACT FROM AUTHOR]

In recent years, research on East Asia, including the China, Japan, South Korea, North Korea and other countries and regions, is gradually valued by a group of young Chinese scholars. Eastern regions studies concentrate on how classical Chinese culture was popularized, absorbed and recreated in East Asia. The four East-Asian countries of China, Japan, South Korea and North Korea are geographical neighbors and mutually dependent upon each other. And in the past two thousand years, the neighbors, separated only by small bodies of water, have been communicating frequently with each other culturally, economically and politically by sea and by land. The Chinese characters that have been used for a long time and the thoughts, religion and literature transmitted through Chinese language constitute the so-called 'Chinese Cultural Circle.' [ABSTRACT FROM AUTHOR]

Composite films containing different amounts of potassium sorbate (KS) were prepared by using fish scale collagen (Col) and polyvinyl alcohol (PVA). Fourier transform infrared spectroscopy (FTIR), light transmittance, mechanical, water vapor transmission rate (WVTR), and the antibacterial properties of the composite films were analyzed. The results showed that the addition of Col significantly reduced the light transmittance of the composite film, but KS had no significant effect on the light transmission. The tensile strength decreased first and then increased with the addition of KS, while the WVTR increased first and then decreased. The composite film exhibited a certain degree of antibacterial properties against E. coli and S. aureus. In addition, we found that ultrasonic treatment reduced the WVTR, and also improved tensile strength and elongation at break of the composite films, but had no significant effect on other properties. The KS/Col/PVA films have the potential to be used as antimicrobial food packaging. [ABSTRACT FROM AUTHOR]