Extension of corrosion inhibitors from traditional molecular-scale to nanoscale will not only be significant to develop green and efficient inhibitors, but also supplement the discipline system of corrosion inhibitors. However, many research on the interfacial behavior of nano-inhibitors have ignored the special colloidal properties of nanoparticles and show no obvious differences with traditional inhibitors. In this study, graphene oxide (GO) was functionalized with polydopamine (PDA) via covalent modifications and self-polymerization, and GO-PDA was studied as a corrosion inhibitor of carbon steel in HCl solution. Diversified measurements confirmed that GO-PDA can effectively protect carbon steel from corrosion, and the inhibition efficiency almost reached 90% at 100 mg/L. Interfering factors including immersion time and concentration were investigated. The lamellar nanoparticles adsorbed on the surface of carbon steel have formed a hydrophobic film in micro-nano structures. The transition from a negative charge on the GO surface to a positively charged GO-PDA contributed to adsorption at the interface. An initial model of nano-inhibitor was established to explicate the inhibition mechanism.
Graphical abstractThe caloric effects under combined applications of magnetic field and hydrostatic pressure to a MnCoSi meta-magnet were investigated. Under a magnetic field change of 0–5 T, the maximum magnetic entropy change was enhanced by 35.7% when a 3.2kbar hydrostatic pressure was applied, and the cooling temperature span was extended by 60 K when a hydrostatic pressure of 9.7 kbar was applied. The coupled caloric entropy change, which originates from the coupling between the magnetism and volume, was calculated and accounted for the enhanced entropy change of MnCoSi. The present work facilitates the use of MnCoSi as a solid-state refrigerant and also enriches the investigation of the multicaloric effect under multiple external fields.
Graphical abstractCarbon nanomaterials have shown great potential as electric heating elements in electrothermal applications. However, carbon-based heating elements with high flexibility, ultrafast electrothermal response, low driving voltage, high heating temperature, and stretchability are still lacking. Here, continuous electrospun carbon nanofiber films (CNFFs) and corresponding composite films additionally containing silicone (CSCFs) as electric heating elements are proposed. CNFFs were prepared by electrospinning and subsequent heat treatment, and CSCFs were prepared by composing CNFFs with silicone via hot-pressing procedure. Both of them have shown excellent performance as electrothermal films, such as ultrafast electrothermal response, high resistance adjustability, high flexibility, high operation stability, and high infrared emissivity. In particular, a temperature as high as 200 °C can be reached within 2 s at 8 V. Suitable robustness and flexibility allow CSCFs to bear various deformations, such as bending, twisting, folding, and even stretching by a factor of 1.3, without worsening electrothermal performance. Also, excellent water resistance has been confirmed. The superior electrothermal performance is mainly attributed to the high electrical conductivity, continuous fiber structure, high specific surface area, and adjustability of nanofiber stacking density and thickness of CNFFs.
Graphical abstractIn view of the disadvantages of concentration polarization and trade-off effects in the application of membrane in desalination field, oxide-nano graphene oxide/polyamide (O-NGO/PA) loose intermediate layer and PA ultra-thin dense layer were introduced to fabricate PA/O-NGO/polyphenylene sulfide composite membrane with sandwich structure via multi-step interfacial polymerization (MS-IP) method. The selective permeation mechanism of ultrathin layer produced by different aqueous monomers (PIP and MPD) was studied, the effect of its physicochemical structure on the relief of concentration polarization phenomenon and the breakthrough of trade-off effect was analyzed. The ultra-thin and dense PA layer mainly played the role of interception and shortened the water molecular penetration path. In the retention test of metal salt solution, compared with the rough surface, it was found that the smooth surface was more conducive to the diffusion of intercepted metal ions into the feed solution, thus alleviating the concentration polarization phenomenon.
Graphical abstractIn this study, poly(L-lactic acid) (PLA)/low molar mass alkali lignin (aL) (1%, 5% and 10% w/w) composites were prepared primarily for a comprehensive understanding of the effect of aL on their antimicrobial properties, biocompatibility and cytotoxic behavior. The properties were evaluated by Fourier transform infrared spectroscopy, scanning electron microscopy, differential scanning calorimetry, thermogravimetry and X-ray diffraction. The mechanical, water vapor barrier properties and photodegradability were analyzed as well. The results showed a significant inhibiting effect of aL on the crystallization behavior of PLA, increased water barrier properties (up to 73%) and photodegradability. PLA/aL composites showed a tenfold reduction in Gram-positive bacteria viability, very good cellular response and very low cytotoxicity levels, thus validating these materials as non-cytotoxic and with high potential to be used as food packaging.
Graphical abstractHere, we report a multiferroic relaxor material 0.41Bi(Ni1/2Zr1/2)O3–0.59PbTiO3, which exhibits a large piezoelectric coefficient (d33, 391 pC/N), high remnant polarization (Pr, 52.3 μC/cm2) and a high electrical freezing temperature (Tf, 498 K). The electric-field-induced transition from a cubic-like phase to a tetragonal phase was confirmed by the XRD patterns and first-cycle bipolar electrostrain loop. The magnetization and magnetic field relationship changes from nonlinear to linear when cooled from 300 to 2 K. The unusual trend in magnetic behavior could be interpreted as the transitions between the super short-range orderings. Furthermore, the maximum value of magnetization shows a 14% decrease at 300 K after electrical poling.
Graphical abstractUtilization of the photon upconversion (UC) in Pb halide-based perovskite solar cells (PVSCs) and photodetectors is a potential strategy towards broadening the spectral response from the visible to the near-infrared region and decreasing the non-absorption loss of solar energy. Nevertheless, the implementation of upconverting nanomaterials in these photoelectric devices still faces some barriers. Herein, we report a facile and ethylenediamine tetraacetic acid disodium (EDTAD)-assisted hydrothermal approach for growth of rare-earth-element-doped KMnF3 nanocrystals with controllable size and a singular red upconverting emission. EDTAD was demonstrated as a useful chelating agent to regulate the nanomaterial size, morphology and UC emission properties. KMnF3:Yb3+, Er3+ nanocrystals assisted by EDTAD achieved an intense single-band red UC emission. The formed singular UCNCs were successfully applied as an additive to enhance the photovoltaic performance of the PVSC devices. We found proper molar ratio UCNCs as an additive to the perovskite precursor facilitated the growth of semiconductor perovskite, inducing the development of the perovskite film with improved crystallinity, compact grains and fewer defects. At an optimum molar proportion of UCNCs, the mean power conversion efficiency (PCE) of 18.73% was acquired for PVSCs with KMnF3:Yb3+, Er3+ under AM 1.5G, demonstrating a prominent improvement over 25% in average PCE relating to the corresponding value (14.94%) of the PVSC device without UCNCs. Moreover, this singular red emission UCNCs-embedded PVSC was able to work as a photodetector under 980 nm illumination and with a responsivity of 0.26 mA/W.
Graphical abstractSilver nanowires find use in a myriad of applications, including communication systems, sensors, medical devices and electrical equipment. Temperature-dependent electrical and thermal properties of chemically derived silver nanowires are rarely explored. In the present work, seed-mediated synthesis of silver nanowires has been carried out, and their electrical and thermal conductivity at 300 K is found to be 1.848?×?107 S/m and 64.8 W/mK, respectively. A screen-printable ink of silver nanowires is formulated and printed on low-cost and widely used substrates like paper and cotton fabrics. Flexible printed electrodes could be made possible with uniform printed structures obtained in cotton fabric and paper substrate. The printed pattern exhibited sheet resistance of 0.7 Ω/sq. Screen-printed silver nanowires on paper show shielding efficiency of 99.9% in X band, which promotes them as excellent candidates in fabricating lightweight electronic devices by a one-step printing process.
Graphical abstractThe properties of nanoparticle–polymer composites strongly depend on the network structure of the polymer matrix. By introducing nanoparticles into a monomer (solution) and subsequently polymerizing it, the formation of the polymer phase influences the mechanical and physicochemical properties of the composite. In this study, semi-conducting indium tin oxide (ITO) nanoparticles were prepared to form a rigid nanoparticle scaffold in which 1,6-hexanediol diacrylate (HDDA), together with an initiator for photo-polymerization, was infiltrated and subsequently polymerized by UV light. During this process, the polymerization reaction was characterized using rapid scan Kubelka–Munk FT-IR spectroscopy and compared to bulk HDDA. The conductivity change of the ITO nanoparticles was monitored and correlated with the polymerization process. It was revealed that the reaction rates of the radical initiation and chain propagation are reduced when cured inside the voids of the nanoparticle scaffold. The degree of conversion is lower for HDDA infiltrated into the mesoporous ITO nanoparticle scaffold compared to purely bulk-polymerized HDDA.
Graphical abstractNanotechnologies known as a developing applied science have significant global socioeconomic values and many advantages obtained from nanoscale materials. Its applications can have significant effects on the performance of organizations. The advance of two-dimensional (2D) MXene-derived QDs (MQDs) is currently in the initial stages. Scholars have shown distinguished optical, electronic, thermal and mechanical attributes by surface chemistry and versatile transition metal. In this field of study, many applications are introduced like energy electromagnetic interference shielding, storage, sensors, transparent electrodes, photothermal therapy, catalysis and so on. The vast range of optical absorption attributes of MQDs along with high electronic conductivity has been detected to be key attributes because of their achievement in the mentioned usages. Currently, relatively little materials are highly known because of their basic electronic and optical properties, which can limit their full potentials. From a theoretical and experimental point of view, in this work, electronic and optical properties of MQDs along with applications corresponding to those properties were evaluated.
Graphical abstractAquivion membrane displays improved properties as compared to Nafion membrane, partly due to shorter side chains. However, some improvements are still necessary for proton exchange membrane fuel cell to operate at low relative humidity. To overcome this drawback, the addition of clay nanoparticle into the Aquivion matrix can be considered. In this study, different composite membranes have been prepared mixing short-side-chain PFSA (perfluorosulfonic acid) Aquivion and selectively modified halloysite nanotubes for PEMFC low relative humidity operation. Halloysites were grafted with fluorinated groups, sulfonated groups, or perfluoro-sulfonated groups on inner or outer surface of the tubes. The obtained composite membranes showed improved properties, especially higher water uptake associated with reduced swelling and better mechanical strength compared to pristine Aquivion membrane and commercially available Nafion HP used as reference. The best performance in this study was obtained with Aquivion loaded with 5 wt% of pretreated perfluoro-sulfonated halloysite. The composite membrane, referred to as Aq/pHNT-SF5, displayed the largest water uptake and proton conductivity among the panel of membranes tested. The chemical stability was not affected by the presence of halloysite in the Aquivion matrix.
Graphical abstractNon-dendritic microstructures are generally obtained in metals after semi-solid deformation (deformation during solidification); however, dendritic growth is preferred without deformation. The fragmentation of dendrites is recognized as an essential contributing factor to non-dendritic microstructures. However, the underlying mechanism of fragmentation needs to be clarified in depth. It is infamously hard for researchers to carry out a direct observation of this process. Moreover, a comprehensive numerical survey of this process is not trivial. The present research reported a new method to model dendritic growth during semi-solid deformation. The motion and deformation of the solid coupled with liquid flow in the melt were treated as the two-phase flow because plastic materials could be formulated as non-Newtonian fluids. The vector-valued phase-field formulation and the self-constructed Navier–Stokes solver made it possible to simulate the growth, motion, deformation, fragmentation and agglomeration of two dendrites coupled with liquid flow in the melt. Computational results suggest that fragmentation can occur when the grain boundary is wet and penetrated by the melt, giving new supporting evidence to a previously proposed mechanism for the fragmentation of dendrites.
Graphical abstractThe development of eco-friendly connection material instead of steel is a challenging problem in timber structures. Following densification, the mechanical properties of low-density species can be significantly improved. Densified wood may be a potential connection material in timber structures. This paper reviewed the different processing for densified wood, and obtained favorable mechanical properties and dimensional stability based on small specimen sizes, which are much less than the applicable sizes in practice. A densification processing with alkali pretreatment was adopted for poplar widely cultivated in the world to produce the densified poplar, which has been rarely reported as connection material. Various specimens of densified poplar were tested to obtain their main mechanical properties such as strength and deformability. The set recovery of densified poplar was also measured to observe their dimensional stability. In addition, the hygroscopic swelling strains for the diameter of densified poplar dowel were measured to present their moisture-dependent behavior. The improved mechanical properties and dimensional stability confirmed the fact that densified poplar with alkali pretreatment can be an optimal connection material.
Graphical abstractIn this work, we systematically investigated the effects of single-step and two-step sintering methods on the structural, dielectric and energy storage properties of pure AgNbO3 lead-free antiferroelectric ceramics. Compared with the single-step sintered ceramic, the ceramic prepared by two-step sintering method has smaller grain size, dense and homogeneous microstructure. In addition, the results of dielectric temperature spectra reveal that the two-step sintering method hardly changes the phase transition temperature of AgNbO3 ceramics but greatly decreases the dielectric loss value. Most importantly, the ceramic prepared by the two-step sintering method displays high breakdown electric field strength (22 kV/mm), larger recoverable energy storage density-Wrec (2.59 J/cm3) and higher energy storage efficiency-η (45%) as well as excellent temperature stability than those of the ceramic by single-step sintering method. Furthermore, it also exhibited high power density (PD?=?25.7 MW/cm3) and extremely fast charge–discharge speed (25 ns). Our results provide a simple and novel way to design high-performance AgNbO3-based energy storage lead-free ceramics.
Graphical abstractPerovskite light-emitting diodes (PeLEDs) have attracted considerable attention due to their low cost, high efficiency and narrowband emission. However, poor operational lifetime limits their practical application and the degradation mechanism is not yet clear. Herein, the effect of typical phenylalkylamine and alkylamine ligands on optoelectrical properties and operational stability of cesium/methylammonium lead bromide PeLEDs were systematically investigated. The phenylethylamine (PEA) modified PeLED shows a champion maximum external quantum efficiency (EQE) of 9.35%, which is much better than that of phenylmethylamine (PMA) and phenylbutylamine (PBA) modified devices. For alkylamine-based devices, the maximum EQEs gradually rise from 2.72 to 6.33% and 6.66% as increase of alkyl chain length. PEA modified device exhibits the best half-lifetime of 114 min and alkylamine-based devices exhibit almost equal T50 of approximately 20 min. X-ray diffraction measurements show that the dominant diffraction peaks of pervoskite films disappear or shift and scanning electron microscope detected that many pinholes appeared in perovskite films after operation. Combining with the results of X-ray photoelectron spectroscopy, we conclude that the recrystallization of perovskite occurred during the operation causes the film change in morphology and crystallinity, ultimately result in the degradation of PeLEDs.
Graphical abstractThe effect of typical phenylalkylamine and alkylamine ligands on optoelectrical properties and operational stability of PeLEDs were systematically investigated. The phenylethylamine modified PeLED shows a champion maximum EQE of 9.35% and the best operational lifetime of 114 min. We concluded that the decomposition and recrystallization of perovskite occurred during the operation causes the film change in morphology and crystallinity, ultimately result in the degradation of PeLEDs.
We review the literature describing the use of interleaves to increase interlaminar fracture toughness in fibre-reinforced polymer composites and hence to improve damage tolerance. From an analysis of data provided in the literature from the use of microfibre and nanofibre interleaves, we show that the performance of these widely researched systems is clearly differentiated when plotted against the mean coverage of the interleaf. Using a simple analysis, we suggest that this can be attributed to the influence of their porous architectures on the infusion of resin. We show also that the superior toughening performance of microfibre interleaves is only weakly influenced by the choice of fibre. We find also that the inclusion of carbon nanotubes within interleaves to deliver multifunctional composites can be optimised by using a hybrid system with microfibres.
Graphical abstractHybrid organic–inorganic nanocomposites are great candidates for display and illumination systems due to improved optoelectronic properties and photostability. This work endeavours towards the scientific study of the influence of defect-induced zinc oxide nanoparticles (ZnO) on the optical characteristics of poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV). ZnO nanoparticles consist of many vacancies which facilitate light emission across the visible region. The green defective emission occurring due to the presence of oxygen vacancies in ZnO was used to re-excite MEH-PPV and hence, improve the luminescence quantum efficiency. The photostability of the nanocomposite was enhanced through charge transfer (prevents the formation of superoxides) and energy transfer (reduces the non-radiative decay) mechanisms.
Graphical abstractLicorice residue, a considerable amount of biomass waste discarded during the excellent extraction process of traditional Chinese medicine every year, is a potential low-cost and green material for the synthesis of porous carbon material. In this work, spinel phase NiCo2O4 nanosheets were produced on the licorice residue-derived nitrogen-doped carbon aerogel (LNCA) using simple hydrothermal and calcination methods. LNCA was first prepared from the carbonation of freeze-dried licorice residue aerogel, which was subsequently utilized to prepare an LNCA/NiCo2O4 composite employing hydrothermal reaction and annealing treatment. As a consequence of its properties, the as-prepared hybrid electrode exhibited ultrahigh capacitance specific capacity (956 F g?1 at 1 A g?1) and long-term stability. This work provides some new insights on the preparation of biomass-derived porous carbon for application in supercapacitors, as well as multifaced considerations.
Graphical abstractOrganic/inorganic thermoelectric composites have played an important role in the development of new, green, and renewable energy sources with potential applications in efficient thermal management, flexible electronics, and bioelectronics. Electrochemical syntheses, including electropolymerization, electrochemical deposition, electrochemical doping, electrochemical post-processing, etc., require no addition of surfactants or oxidants, the products of which are easy to separate and purify, providing clean, efficient, and facile routes for the preparation of organic thermoelectric materials and their composites. In this review, the preparation, properties, and applications of organic/inorganic thermoelectric composites from electrochemical synthesis were reviewed in detail, offering a perspective on the recent advances in the field.
Graphical abstractSilica aerogel composites reinforced with different aramid fibres have been synthesized and compared considering their potential use in thermal protection systems of Space devices. These composites were prepared from tetraethoxysilane and vinyltrimethoxysilane and the network was strengthened with aramid fibres. The results showed that the physical and chemical properties of the fibres were relevant, leading to composites with different properties/performance. In general, the obtained values for bulk density were low, down to 150 kg m?3. Very good thermal properties were achieved, reaching thermal conductivities bellow 30 mW m?1 K?1, and thermal stability up to 550 °C in all cases. Short length fibres produce stiffer composites with lower thermal conductivities, while among longer fibres, meta-aramid-containing fibres lead to nanocomposites with best insulation performance. Standard tests for Space materials qualification, as thermal cycling and outgassing, were conducted to assess the compliance with Space conditions, confirming the suitability of these aerogel composites for this application.
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