查看更多>>摘要：High-performance electromagnetic (EM) wave absorption and shielding materials integrating with flexibility, air permeability, and anti-fatigue characteristics are of great potential in portable and wearable electronics. These materials usually prepared by depositing metal or alloy coatings on fabrics. However, the shortcomings of heavy weight and easy corrosion hamper its application. In this work, the cellulose nanofiber (CF) fabric was prepared by electrospinning technology. Then, conductive polyaniline (PANI) was deposited on the CF surface via a facile in-situ polymerization process. The interweaving cellulose/polyaniline nanofiber (CPF) composite constructs a conductive network, and the electrical conductivity can be adjusted by polymerization time. Benefiting from optimal impedance matching, strong conductive loss, as well as interfacial polarization, the CPF possesses excellent EM absorption performance. The minimum reflection loss (RLmin) value is -49.24 dB, and the effective absorption bandwidth (RL < -10 dB, fe) reaches 6.90 GHz. Furthermore, the CPF also exhibits outstanding electromagnetic interference (EMI) shielding capability with shielding efficiency (SE) of 34.93 dB in the whole X band. Most importantly, the lightweight CPF fabrics have the merits of mechanical flexibility, breathability and wash resistance, which is highly applicable for wearable devices. (c) 2021 Published by Elsevier Inc.
查看更多>>摘要：Dynamic interfacial tension was studied experimentally during drop formation in a flow-focusing microchannel. A low viscosity silicone oil (4.6 mPa s) was the continuous phase and a mixture of 48% w/w water and 52% w/w glycerol was the dispersed phase. An anionic (sodium dodecylsulfate, SDS), a cationic (dodecyltrimethylammonium bromide, DTAB) and a non-ionic (TritonTM X-100, TX100) surfactant were added in the dispersed phase, at concentrations below and above the critical micelle concentration (CMC). For SDS and DTAB the drop size against continuous phase flowrate curves initially decreased with surfactant concentration and then collapsed to a single curve at concentrations above CMC. For TX100 the curves only collapsed at surfactant concentrations 8.6 times the CMC. From the collapsed curves a correlation of drop size with capillary number was derived, which was used to calculate the dynamic interfa-cial tension at times as low as 3 ms. The comparison of the surfactant mass transport and adsorption times to the interface against the drop formation times indicated that surfactant adsorption also con-tributes to the time required to reach equilibrium interfacial tension. Criteria were proposed for drop formation times to ensure that equilibrium interfacial tension has been reached and does not affect the drop formation. (C) 2021 The Authors. Published by Elsevier Inc.
查看更多>>摘要：Although a number of nanozymes have been developed, it is still difficult to develop single-component nanozyme with overall high multienzyme-like activities. In this study, the nanosized metal-organic frameworks (nano-MOFs) FePCN (PCN stands for porous coordination network) was synthesized by inte-grating zirconium and iron ions with different catalytic property on single-component MOFs and exhib-ited superior intrinsic multienzyme-like activities, namely oxidase-, peroxidase-and phosphatase-mimicking activity. The catalytic active sites of oxidase-and peroxidase-, and phosphatase-like activity of FePCN were Fe-centers and Zr-O clusters, respectively. Based on the intrinsic oxidase-like activity and the similarity of molecular structures between cytochrome P450 oxidase (CYP) cofactors and the organic linker in FePCN, FePCN exhibited high CYP-like activity to catalyze the oxidation of hypotensive drug 1,4-dihydropyridine (1,4-DHP) into diethyl 2,6-dimethylpyridine-3,5-dicarboxylate (DDPD) and the yield of DDPD reached over 80%. Moreover, as peroxidase-and phosphatase-mimics, FePCN was successfully applied to detecting H2O2 under neutral condition and catalyzing the dephosphorylation of adenosine triphosphate (ATP), respectively. This study provides a feasible way for rational design one component nanomaterials as multienzyme-mimics. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：The unstable electrode/electrolyte interface of the lithium metal anode is one of the reasons that induce the formation of lithium (Li) dendrites. The Li dendrites will reduce the coulombic efficiency, and even pierce the separator to cause the safety problems. Herein, a tightly bonded and uniformly distributed Cu6Sn5 interface layer is formed on the surface of the Cu foam by a simple electroless plating method. The composite layer has multiple functions, such as high lithiophilicity, high carrier transport and high adaptability to mechanical strain. Based on the versatility of the Cu6Sn5 interface layer, the cycle life of Cu foam is increased from 150 h to 1000 h, and the deposition overpotential is as low as 18 mV. In situ online observation proves that the existence of composite layer can make Li metal uniformly deposited to avoid the dendrites. Furthermore, Cu6Sn5@Cu foam also shows a higher capacity retention rate (increased from 65.2% to 78.6% after 300 cycles) and a more stable rate performance when it is used in full batteries. Compared with the single function improvement strategy proposed by the current lithium metal anode research. The Cu6Sn5 multifunctional composite layer modification method in this work provides a new strategy for constructing a stable electrode/electrolyte interface. (C) 2021 Published by Elsevier Inc.
查看更多>>摘要：Flexible electrode plays a key role in flexible energy storage devices. The SnTe/C nanofibers membrane (SnTe/CNFM) with excellent mechanical flexibility has been successfully synthesized for the first time through electrospinning, and it demonstrates outstanding electrochemical performance as free-standing anode for lithium/sodium-ion batteries. The SnTe/CNFM electrode delivers a discharge capacity of 526.7 mAh g(-1) at 1000 mA g(-1) after 1000 cycles in lithium-ion half-cells and a discharge capacity of 236.5 mAh g(-1) at 500 mA g(-1) after 80 cycles in lithium-ion full-cells with a LiFePO4 cathode. Not only that, it shows a discharge capacity of 182.7 mAh g(-1) at 200 mA g(-1) after 200 cycles in sodium-ion half-cells and a high discharge capacity of 207.0 mAh g(-1) at 500 mA g(-1) after 50 cycles in sodium-ion full-cells with a Na0.44MnO2 cathode. Moreover, the prepared SnTe/CNFM exhibits good mechanical flex-ibility. The SnTe/CNFM can still return to its original state without any breakage after bending, curling, folding and kneading. These results indicate that SnTe/CNFM is expected to become one of the promising free-standing anodes for lithium/sodium-ion batteries. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：SiO2@(3)COFs@CuO and SiO2@(3)COFs@Fe2O3 are prepared in this study. Then SiO2 and its hybrids are incor-porated into PS through solution blending method. The thermal stability, mechanical performance, com-bustion performance and smoke density of PS and its nanocomposite are investigated. The temperature at 5 wt% weight loss and the maximum weight loss rate of PS/SiO2@(3)COFs@ Fe2O3 (PS 4) under air are 15 and 14 degrees C higher than that of neat one, respectively. The glass-transition temperature of PS/SiO2@(3)COFs (PS 2) is 1.5 degrees C lower than that of PS, which can conclude that SiO2@(3)COFs contributes to impact strength of PS 0. The peak heat release rate (20.8%) and total heat release (14.0%) of PS 2 decreases further com-pared with that of PS 0. The smoke density of PS 4 is 23.1% lower than that of neat PS. The influence of SiO2 and its nano-hybrids on the pyrolysis and combustion of PS is investigated. Incorporation of SiO2 and its nano-hybrids shows little effect on pyrolysis process of PS. However, heat resistance of PS is enhanced obviously and thermal degradation rate of PS is also decreased through incorporation of SiO2 and its nano-hybrids. The gaseous pyrolysis products (aromatic compounds and alkenyl compounds) of PS and its nanocomposite also decrease. (C) 2021 Published by Elsevier Inc.
查看更多>>摘要：Designing and constructing advanced heterojunction architectures are desirable for boosting CO2 photoreduction performance of semiconductor photocatalysts. Herein, we have prepared hierarchical ZnS@ZnIn2S4 core-shell cages with controlled particle sizes using sequential synthesis of Zeolitic imidazolate (ZIF-8) polyhedrons, ZnS cages, and ZnIn2S4 nanosheets on the ZnS polyhedron cages. ZIF-8 polyhedrons are firstly synthesized by a liquid-phase approach. The subsequent sulfidation of the ZIF-8 polyhedrons results in the formation of ZnS polyhedron cages, which act as substrates for fabricating ZnS@ZnIn2S4 core-shell cages by growing ZnIn2S4 nanosheets. The size of ZnS cages can be tuned to optimize CO2 photoreduction performance of hierarchical ZnS@ZnIn2S4 core-shell cages. The synergy of the unique hierarchical core-shell cage-like structure and heterojunction composition endows the hybrid catalyst high incident light utilization, abundant active sites, and effective separation of photoexcited charge carriers. Benefiting from these advantages, the optimized hierarchical ZnS@ZnIn2S4 core-shell cages exhibit enhanced performance for CO2 photoreduction with the CO yield of 87.43 mu mol h(-1) g(-1) and 84.3% selectivity, which are much superior to those of single ZnIn2S4 or ZnS. Upon Au decoration, the CO2 photoreduction performance of ZnS@ZnIn2S4 core-shell cages is further enhanced because of the Schottky junctions and surface plasmon resonance effect. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：Calcium based biomaterials were widely used for drug delivery application due to their biodegradability, biocompatibility, and high drug loading capacity. Herein, amino-capped polyamidoamine (PAMAM) dendrimer was applied as a macromolecular template to form amino-modified calcium phosphate hollow sphere (CaPO-NH2). After loading with 5-fluorouracil (5Fu), this system performed synergistic cancer chemotherapy. In this study, the 5Fu/CaPO-NH2 particles could be efficiently uptaken by cancer cells, and then decompose into Ca2+ and release 5Fu drug in the cytoplasm; therefore calcium overload and reactive oxygen species (ROS) accumulation were found in PSN1 cells that could induce cell membrane damage and elicit cell apoptosis through a series of biochemical reactions including endoplasmic reticulum stress, lipid peroxidation and mitochondrial apoptosis. In the PSN1 pancreatic cancer xenograft model, the 5Fu/CaPO-NH2 system performed high tumor inhibition via chemotherapy and calcium overload induced apoptosis. Comparingly, the normal cells and organs were insensitive to this synergistic therapy, which indicated the well biocompatibility of delivery system. Thus, this study provided a promising CaPO-NH2 drug delivery platform for enhanced 5Fu chemotherapeutic effect. (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：The assembly of functional nanoparticles within materials with unique architectures can improve the interfacial surfaces, defects, and active sites, which are key factors for the designing novel nanocatalysts. Nano metal-organic framework (NMOF) can be employed to fabricate nanodots-confined nanohybrids for use in electrocatalytic processes. Herein, we report a controlled synthesis of gold nanodot assembly within cobalt chalcogenide nanoshell (dots-in-shell Au/CoxSy nanohybrids). A cobalt-based NMOF (the cobalt-based zeolite imidazole framework, ZIF-67) is used as a versatile sacrificial template to yield dots-in-shell Au/CoxSy nanohybrids. Due to the synergistic effect of the well-dispersed Au nanodots and the thin CoxSy nanoshell, the obtained dots-in-shell Au/CoxSy nanohybrids exhibit enhanced performance for the oxygen evolution reaction (OER) with low overpotential values at a current density of 10 mA cm(-2) and a small Tafel slope (343 mV and 62 mV dec(-1), respectively). (C) 2021 Elsevier Inc. All rights reserved.
查看更多>>摘要：Hypothesis: We developed a geometrical model to determine the theoretical maximum number of pro -teins that can pack as a monolayer surrounding a spherical nanoparticle. We applied our new model to study the adsorption of receptor binding domain (RBD) of the SARS-CoV-2 spike protein to silica nanoparticles. Due to its abundance and extensive use in manufacturing, silica represents a reservoir where the virus can accumulate. It is therefore important to study the adsorption and the persistence of viral components on inanimate surfaces. Experiments: We used previously published datasets of nanoparticle-adsorbed proteins to validate the new model. We then used integrated experimental methods and Molecular Dynamics (MD) simulations to characterise binding of the RBD to silica nanoparticles and the effect of such binding on RBD structure. Findings: The new model showed excellent fit with existing datasets and, combined to new RBD-silica nanoparticles binding data, revealed a surface occupancy of 32% with respect to the maximum RBD pack-ing theoretically achievable. Up to 25% of RBD's secondary structures undergo conformational changes as a consequence of adsorption onto silica nanoparticles. Our findings will help developing a better understanding of the principles governing interaction of pro -teins with surfaces and can contribute to control the spread of SARS-CoV-2 through contaminated objects. (c) 2021 Elsevier Inc. All rights reserved.
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