Special Three-dimensional Structure Research Articles

Biomimetic multi-functional 3D fog collector: Independent of fog flow direction

The shortage of freshwater resources has a great impact on the daily life of human beings, and fog collection has become an effective mitigation measure. In this paper, inspired by the nanofabricated desert beetle, honeycomb, Euphorbia antiquorum L. and cactus, a 3D fog collector combining a conical array structural gradient and a wettability gradient was presented, with special three-dimensional array structure (TA-L/B (PPC)) that ensures that the fog-collecting efficiency of the samples is virtually independent of the direction of the fog flow. The fog collection efficiency of sample TA-L/B (PPC) is close to 4.3 g·h−1·cm−2, a value that is 1.77 times higher than the surface fog collection efficiency of the copper sheet (OS) sample. By rationally designing the surface structure of the sample, the fog circulation process is accelerated, and a sustainable and stable fog collection process is achieved.

Crystalline CdS/Amorphous Cd(OH)2 Composite for Electrochemical CO2 Reduction to CO in a Wide Potential Window.

Electrochemical CO2 reduction is a promising method for converting atmospheric CO2 into valuable low-carbon chemicals. In this study, a crystalline cadmium sulfide/amorphous cadmium hydroxide composite was successfully deposited on the carbon paper substrate surface by in-situ chemical bath deposition (named as c-CdS/a-Cd(OH)2/CP electrodes) for the efficient electrochemical CO2 reduction to produce CO. The c-CdS/a-Cd(OH)2/CP electrode exhibited high CO Faradaic efficiencies (>90 %) under a wide potential window of 1.0 V, with the highest value reaching ~100 % at the applied potential ranging from -2.16 V to -2.46 V vs. ferrocene/ferrocenium (Fc/Fc+), superior to the crystalline counterpart c-CdS/CP and c-CdS/c-Cd(OH)2@CP electrodes. Meanwhile, the CO partial current density reached up to 154.7 mA cm-2 at -2.76 V vs. Fc/Fc+ on the c-CdS/a-Cd(OH)2/CP electrode. The excellent performance of this electrode was mainly ascribed to its special three-dimensional structure and the introduction of a-Cd(OH)2. These structures could provide more active sites, accelerate the charge transfer, and enhance adsorption of *COOH intermediates, thereby improving the CO selectivity. Moreover, the electrolytes consisting of 1-butyl-3-methylimidazolium tetrafluoroborate and acetonitrile also enhanced the reaction kinetics of electrochemical CO2 reduction to CO.

Large-scale vertical graphene on nickel foil as a binder-free electrode for high performance battery-like supercapacitor with an aqueous redox electrolyte

Due to the special three-dimensional structures and excellent physicochemical properties, vertical graphene (VG) has been extensively investigated as potential material for supercapacitors. However, achieving VG-based supercapacitors with high-energy density and high-power density is a still tremendous challenge. Here we attempt to synthesize large-scale VG films on flexible substrates and design a novel battery-like supercapacitor (BSCs) with the VG on Ni foil (VG@Ni) as a binder-free electrode operating in the KOH electrolyte with the redox additives of K3Fe(CN)6 and/or K4Fe(CN)6. The VG@Ni electrodes demonstrate an ultrahigh areal capacitance of 1453 mF cm−2 at 5 mA cm−2 in 1 M KOH electrolyte with adding 0.07 M K3Fe(CN)6 and 0.07 M K4Fe(CN)6, coulombic efficiency greater than 90%, and long-life cycling stability (capacitance retention is 99.3% after 20000 charge-discharge cycles). The BSCs, which are assembled with two identical VG@Ni electrodes, deliver the areal capacitance of 231 mF cm−2 with energy density of 32 μWh cm−2 and power density of 2498 μW cm−2 at 1 mA cm−2. These outstanding performances can be ascribed to the special feature and excellent properties of VG materials, high electronic conductivity of binder-free VG@Ni electrode, faradaic properties of redox electrolyte, and synergistic effects between the VG film and redox electrolyte.

Construction of nitrogen-doped graphene-based ternary magnetic composite aerogel towards excellent electromagnetic absorption in the Ku-band

The development of advanced electromagnetic wave (EMW) absorbing materials with broad bandwidth, strong absorption, low filler loading ratio and small thickness remains a great challenge. In this work, nitrogen-doped reduced graphene oxide/multi-walled carbon nanotubes/hollow nickel ferrite (NRGO/MWCNTs/hollow NiFe2O4) ternary magnetic composite aerogel with the ultralow bulk density was synthesized via the two-step route of solvothermal synthesis and hydrothermal self-assembly. Results of microscopic morphology characterization showed that as-synthesized binary and ternary magnetic composite aerogels exhibited the special three-dimensional hierarchical porous network structure. Moreover, the EMW absorption performance of ternary composite aerogel was obviously enhanced in comparison with NRGO/MWCNTs and NRGO/hollow NiFe2O4 binary composite aerogels. Remarkably, the attained NRGO/MWCNTs/hollow NiFe2O4 ternary composite aerogel showed the maximum absorption bandwidth of 6.7 GHz (11.3–18.0 GHz) and robust absorbing intensity of − 42.8 dB at a thin matching thickness of 2.0 mm and a low loading ratio of 12.5 wt%. It was worth noting that when the matching thickness was slightly increased to 2.1 mm, the optimal minimum reflection loss could reach − 69.0 dB. The special hierarchical porous network structure and magnetodielectric synergy in the ternary composite aerogel optimized the impedance matching, and notably enhanced the EMW absorbing capacity. Therefore, this work could contribute to the construction of graphene-based hybrid nanocomposites as advanced EMW absorbers.

Heteropolyacid Ionic Liquid-Based MCF: An Efficient Heterogeneous Catalyst for Oxidative Desulfurization of Fuel.

A new type of catalyst was synthesized by immobilizing heteropolyacid on ionic liquid-modified mesostructured cellular silica foam (denoted as MCF) and applied to the oxidative desulfurization of fuel. The surface morphology and structure of the catalyst were characterized by XRD, TEM, N2 adsorption-desorption, FT-IR, EDS and XPS analysis. The catalyst exhibited good stability and desulfurization for various sulfur-containing compounds in oxidative desulfurization. Heteropolyacid ionic liquid-based MCF solved the shortage of the amount of ionic liquid and difficult separation in the process of oxidative desulfurization. Meanwhile, MCF had a special three-dimensional structure that was not only highly conducive to mass transfer but also greatly increased catalytic active sites and significantly improved catalytic efficiency. Accordingly, the prepared catalyst of 1-butyl-3-methyl imidazolium phosphomolybdic acid-based MCF (denoted as [BMIM]3PMo12O40-based MCF) exhibited high desulfurization activity in an oxidative desulfurization system. The removal of dibenzothiophene could achieve levels of 100% in 90 min. Additionally, four sulfur-containing compounds could be removed completely under mild conditions. Due to the stability of the structure, sulfur removal efficiency still reached 99.8% after the catalyst was recycled six times.

Latest Progress of Mechanical Properties of Geopolymer Concrete at Elevated Temperature

In order to alleviate the environmental pollution and energy consumption problems caused by ordinary Portland cement, geopolymer came into being as a new type of green building material. The special three-dimensional mesh structure of geopolymer concrete makes it show excellent durability under fire, so it has been deeply studied by many scholars. This paper mainly expounds the research results of the basic static properties of inorganic geopolymer concrete at high temperature from the following four aspects: compressive strength, tensile strength, modulus of elasticity and stress-strain relationship. Due to the obvious differences in the mechanical and structural properties of geopolymer concrete in terms of raw materials, mix ratio, curing temperature, etc. There is no corresponding material and structural design specification for geopolymer concrete and it needs more incisive research before it applies to engineering construction.

Research Progress of Polysaccharide-Based Natural Polymer Hydrogels in Water Purification.

The pollution and scarcity of freshwater resources are global problems that have a significant influence on human life. It is very important to remove harmful substances in the water to realize the recycling of water resources. Hydrogels have recently attracted attention due to their special three-dimensional network structure, large surface area, and pores, which show great potential for the removal of pollutants in water. In their preparation, natural polymers are one of the preferred materials because of their wide availability, low cost, and easy thermal degradation. However, when it is directly used for adsorption, its performance is unsatisfactory, so it usually needs to be modified in the preparation process. This paper reviews the modification and adsorption properties of polysaccharide-based natural polymer hydrogels, such as cellulose, chitosan, starch, and sodium alginate, and discusses the effects of their types and structures on performance and recent technological advances.

Biomass-Based Anion Exchange Membranes Using Poly (Ionic Liquid) Filled Bacterial Cellulose with Superior Ionic Conductivity and Significantly Improved Strength

ABSTRACT How to simultaneously improve the ionic conductivity and mechanical properties is a key problem facing currently used anion-exchange membranes (AEMs). Here, novel AEMs were prepared using quaternized bacterial cellulose (QBC) as a dual-functional substrate and then filled with a polymeric ionic liquid (poly(vinylbenzyl) trimethylammonium chloride, PVD) with high ion-exchange capacity through in situ polymerization and crosslinking. The dense quaternary ammonium groups grafted on the surface of BC nanofibers greatly increased the ionic conductivity, while the special three-dimensional network structure of BC significantly enhanced the tensile strength and chemical stability of the obtained PVD filled quaternized BC (QBC/PVD) membranes. The ionic conductivity of QBC/PVD membrane reached as high as 111 mS cm−1 at 80°C, which was 109% higher than that of the pure BC/PVD membrane (only 53 mS cm−1). Moreover, the QBC/PVD membrane exhibited extremely high dry strength of 72.3 MPa and satisfactory wet strength and flexibility, this membrane can hang a container containing 500 g of water when at fully hydrated state. The alkaline direct methanol fuel cell equipped with QBC/PVD output a peak power density of 64 mW cm−2, showing its great application potential as an AEM.

Origami tunable frequency selective fabric and its tuning mechanism

The tunable frequency selective surface can change its resonant frequency to better meet the complex and changeable electromagnetic (EM) environment. The traditional metal frequency selective surface (FSS) has high precision, but it is hard, making it not easy to bend and adapt to the surface. In this paper, an origami tunable frequency selective fabric (oTFSF) is proposed, which is thin, flexible, and bendable with precise resonant frequency adjustment function. The oTFSF is made by folding and ironing a single layer of FSF with a special three-dimensional spatial structure. By changing its state, the angle of the EM wave interacting with conductive units of the oTFSF can be altered to realize the precise adjustment of the resonant frequency. When the folding trace is parallel to the electric field, the three-dimensional structure of the oTFSF can be equivalent to the projected plane structure through simulation. Therefore, multiple oblique incidence situations can be converted into vertical incidence situations. The equivalent EM parameters of the oTFSF can be obtained by particle swarm optimization algorithm (PSO) to analyze the influence of unit size change on oTFSF. The results show that when the folding angle increases, the equivalent inductance (L) decreases, and the equivalent capacitance (C) increases. The oTFSF can be used to prepare intelligent EM functional materials with characteristics of broadband, lightweight, flexible, and adjustable frequency.

One-step construction of P(AM-DMDAAC)/GO aerogel evaporator with Janus wettability for stable solar-driven desalination

The interfacial solar evaporation, as a promising energy-efficient desalination technology, still urgently requires the development of efficiency and salt-resistance of the three-dimensional evaporators. Herein, Janus aerogels with macroporous air capsule structure were prepared by one-step hydrothermal self-assembly and freeze-drying treatment of dimethyldiallylammonium chloride acrylamide polymer-graphene colloidal solution, and then used for photothermal evaporation of high salt wastewater. The Janus P(AM-DMDAAC)/GO aerogels (PGA) exhibited asymmetric wettability and roughness at their upper and bottom surfaces, which are favorable for photothermal conversion at the hydrophobic interface and sufficient water supply at the hydrophilic interface. The evaporation rate of 3.65 kg m−2h−1 and the photothermal conversion efficiency of 98.9 % were obtained under 1.0 sun irradiation, which was attributed to the special three-dimensional structure of the Janus PGA. Benefited from the excellent water supply properties and the special air capsule framework, the as-obtained Janus PGA evaporator exhibited robust recyclability and durability in simulated seawater for 10 d without any salt crystallization. This study provides a simple strategy toward construct Janus aerogels with macroporous air capsule structure for solar evaporation and high-salinity wastewater treatment.

Efficient synthesis of PdIr nanocatalysts with controllable surface composition for electrochemical oxidation of methanol

Pure iridium (Ir) is easy to produce OH adsorbent species and has a wide range of applications in electrocatalysis. The structure–activity relationship between controlled synthesis and surface regulation of Ir-based alloys and their properties needs further study.When P123(poly (ethylene oxide)-poly (ethylene oxide)-poly (ethylene oxide)(PEO20-PPO70-PEO20) is used as reducing agent and protective agent, the ir-rich core–shell structure PdIr@Ir catalyst can be obtained by the solution thermal method without adding KI, and the PdIr alloy can be obtained after the addition of KI. The complexation ability of KI can change the reduction rate of the precursor and regulate the surface composition of the catalyst.After optimizing the dose of KI, the PdIr-4 shows the highest methanol oxidation reaction (MOR) activity and anti-CO toxicity.The PdIr-2 catalysts with rich Ir on the surface showed high stability, possibly due to the gradual activation of Ir on the surface by PdIr inside. The results of experimental characterization and theoretical calculations show that the main reasons for the performance improvement of PdIr series catalysts are the special three-dimensional structure of PdIr, the bifunctional mechanism between Pd and Ir, especially the synergistic catalytic action of Ir and the effect of regulating the electron structure.The experimental results of this paper are expected to provide some ideas and guidance for Ir-based catalysts with high activity and high stability.

A novel graphite modified paper based cobalt-cobalt oxalate-nickel electrode for the electrooxidation of hydrogen peroxide

The use of fossil energy has caused a serious burden on the environment, so it is urgent to find new and developable energy sources. H2O2 as a new type of clean fuel for fuel cell has received widespread attention. In this paper, a novel graphite modified paper based cobalt-cobalt oxalate-nickel ([email protected]–CoC2O4–Ni) electrode is fabricated by the simple “pencil depicting-electrodeposition-oxalic acid etching-electrodeposition” process for the electrooxidation of H2O2 in alkaline environment. The as-prepared [email protected]–CoC2O4–Ni electrode owns a novel and special three-dimensional (3D) porous structure, which can greatly increase the diffusion of reactants (NaOH and H2O2) during the electrochemical reaction process and lead a high catalytic activity for the electrooxidation of H2O2. More importantly, three main nanomaterial (Co, CoC2O4 and Ni) and some new generated substances during the CV test in NaOH solution (e.g. Ni(OH)2, NiOOH, Co(OH)2, CoOOH, Co3O4 and Co2O3 etc.) are on the surface of paper, which will enhance the electrocatalytic activity of the [email protected]–CoC2O4–Ni electrode to a great extent due to their synergistic effect. When the reaction solution contains 1.0 mol dm−3 NaOH and 0.2 mol dm−3 H2O2, the [email protected]–CoC2O4–Ni electrode exhibits a much higher oxidation current density (270.6 mA cm−2) than the FG, [email protected], [email protected], [email protected]–Ni and [email protected]–CoC2O4 electrodes. Besides, the whole preparation process for the [email protected]–CoC2O4–Ni electrode doesn't use any organic binder, ensuring the electrode owns good conductivity and stability for the electrochemical reaction. At last, the electrocatalytic mechanism for the electrooxidation of H2O2 is discussed. The Ni compounds and Co compounds are believed as the main catalytic substances, and the metallic Co core provides a fast route for the transfer of electrons. The super catalytic activity makes the prepared electrode in this study to be a promising material for the electrooxidation of H2O2 and the novel design idea gives some guidance for the fabrication of electrode materials in the field of fuel cell.

Preparation and Characterization of Gaphene-Doped Carbon-Aerogel Electrode

Carbon-aerogel is a kind of nano-porous carbon material with special three-dimensional network structure. Electrode materials with high specific surface area, high porosity, superior conductivity and low density were obtained by adding graphene to prepare graphene-doped carbon-aerogels.

YSZ-Based Mixed Potential Type NH3 Sensor Attached with Ag Doped FeVO4 Sensing Electrode

Introduction In an automobile selective catalytic reduction (SCR) system, the monitoring of NH3 concentration is of vital importance. NH3 detection in such harsh environment of high temperature and humidity is an almost impossible task for most testing methods. Nevertheless, YSZ-based mixed potential type gas sensor is an incomparable choice. Moreover, the development and utilization of sensing electrode materials is an effective method to develop high performance YSZ-based mixed potential type ammonia gas sensor [1]. FeVO4, a n-type semiconductor with direct band gap, is considered as a promising sensing electrode material due to its special three-dimensional layered structure [2]. Ag was reported to have excellent catalytic activity. Through Ag collaborating with the sensing electrode, the response of the NH3 sensor could be enhanced accompanied by the improved sensitivity and detection limit [3]. In this study, we prepared FeVO4 through the sol-gel method. Then, Ag doped FeVO4 in different molar ratio (1.5, 2.5, 3.5 and 4.5 mol.%) was synthesized through the sodium borohydride reduce method and used as sensing electrode material of the YSZ-based mixed potential type NH3 gas sensor. The effects of different molar ratios Ag doped on the NH3 sensing performance were studied. The sensor attached with 3.5 mol.% Ag doped FeVO4 displays high response to target NH3 gas, short response and recovery time, satisfying humidity resistance and good repeatability, indicating its potential for in-situ ammonia monitoring for automotive applications [4]. Method Fabrication and measurement of the gas sensor The sensor was fabricated on a YSZ plate (8 mol. % Y2O3 doped, 2 mm × 2mmsquare, 0.2 mm thickness), provided by Anpeisheng Corp. China. A point-shaped electrode and a narrow stripe-shaped electrode were formed on the two sides using a commercial Pt paste (Sino-platinum Metals Co. Ltd.), and sintered at 1000°C. The sensing material was mixed with a minimum quantity of deionized water and the resultant paste was applied on the point-shaped Pt to form stripe-shaped SE and then sintered at 800 °C for 2 h. The testing method of the sensor was as showed in our previous work [5]. Results and Conclusions A series of sensing tests showed the sensor attached with 3.5 mol.% Ag doped FeVO4-SE had the highest response to NH3, as Fig.1a shows. The reason that the sensor attached with 3.5 mol.% Ag doped FeVO4-SE have the highest sensing performance is due to best electrochemical catalytic activity to NH3 of the sensing electrode materials. The best electrochemical catalytic activity of the material will be proved by the polarization curves and complex impedance test in the future. The NH3 sensing performance of the sensor attached with 3.5 mol.% Ag doped FeVO4 was studied at different operating temperatures and the optimal operating temperature was determined at 550 °C, as Fig.1b shows. The sensor could even detect as low as 200 ppb NH3 with the response of -3.2 mV, as shown in Fig.1 c. Also, the sensor had a good reproducibility as shown in Fig.1 d. Moreover, the sensor displayed good selectivity to NH3 when compared to other interfering gases such as NO2, SO2, C2H2 and CO, as shown in Fig.1 e. For accurate and rapid detection of NH3, the response and recovery time is a vital indicator. In the present research, the typical 90% response time to 50 ppm NH3 of the sensor was less than 3 s as shown in Fig.1 f. In the actual working condition, the exhaust gas is always of high humidity. Therefore, the environmental humidity’s influence on the NH3 sensor was studied and the result in F ig.1g and h showed that the sensor had an acceptable humidity stability. Based on the above results, the sensor we fabricated is prospective in automobile selective catalytic reduction (SCR) exhaust gas treatment system.

Rational design of a cobalt sulfide/bismuth sulfide S-scheme heterojunction for efficient photocatalytic hydrogen evolution

Following a simple one-pot hydrothermal method, a Co9S8/Bi2S3 composite was successfully synthesized using peanut-like BiVO4 as a precursor. After hydrothermal sulfuration, BiVO4 was transformed into Bi2S3 while maintaining its original peanut-like structure. Meanwhile, Co9S8 nanoparticles were successfully coated onto the peanut-shaped surface of Bi2S3, forming an S-scheme heterojunction by in situ hydrothermal method. For the growth system of Co9S8, the special three-dimensional (3D) structure of Bi2S3 provides a good growth site for zero-dimensional (0D) Co9S8 nanoparticles, avoiding their aggregation and exposing, more reaction area of Co9S8. Moreover, the S-scheme heterojunction retains a more effective redox potential for this system and promotes the recombination of nonessential electron-hole pairs. The 0D/3D spatial structure and the construction of the S-scheme heterojunction provide a more efficient and convenient path for the transfer of photogenic charge, which greatly promotes the effective separation and diversion of the electrons. Besides, the cladding structure of the composite and the S-scheme heterojunction formed between Bi2S3 and Co9S8 complement each other for jointly improving the hydrogen production performance of Co9S8/Bi2S3.

Numerical simulation of a fully solid-state micro-unit regeneration magnetic refrigerator with micro Peltier elements

As an alternative to the vapor-compression technology, magnetic refrigeration has been an active area of research in recent years. A serious obstacle faced by existing magnetic refrigeration prototypes is the use of a heat-transfer fluid, which may result in high irreversible losses, large pressure drops and complex fluid circuits. Solid-state magnetic refrigeration has been investigated as a potential solution. For our previously proposed solid-state micro-unit regeneration magnetic refrigerator, the special three-dimensional structure design allows the heat to be regenerated at a small temperature difference. It is note-worthy that a three-dimensional numerical simulation is necessary for analysing the internal heat transfer characteristic and revealing the operation parameters matching rule of micro-unit regeneration cycle. Therefore, in this work a three-dimensional solid-state magnetic refrigerator based on micro-unit regeneration cycle and Peltier elements is modelled in detail. Multiple micro Peltier (9506-063-022M) modules are coupled with a system to enhance the heat regeneration between the magnetocaloric material lattices. The reliability of the model, in parts and in whole, is verified by experimental data. The heat transfer process and performance characteristics are carefully compared and discussed for several configurations, including the system with/without Peltier elements, two types of lattice heat-transfer structures, different Peltier’s input voltages, and different required times for rotation per lattice. The results show that a larger temperature span and higher frequency are obtained when coupled with Peltier elements. Meanwhile, the parallel-plate heat transfer structure of the magnetocaloric material lattice further improves the performance of the system. The optimal system performance is simultaneously determined by the input voltage and rotating speed. Using gadolinium as a magnetocaloric material and in the case of a 0.7 T applied magnetic field, a maximum temperature span of 32 K, an optimal coefficient of performance of 5.45, and a maximum specific cooling power of 252.5 W/kg can be achieved in such a fully solid-state micro-unit regeneration magnetic refrigeration system. The simulation results can serve as guidelines for solid-state magnetic refrigerator design and optimisation.

Preparation and Characterization of Hollow Zinc Oxide Nanofibers and Investigation of Its Photocatalytic Properties

Hollow inorganic nanofibers have great potential application in the field of photocatalysis due to their special three-dimensional structure. In our work, we have fabricated ZnO hollow nanofibers (ZnO-HNF) by simple single-spinneret electrospinning of polyacrylonitrile (PAN)/zinc acetate precursor solution, followed by stepwise annealing at 300–500 °C. The results show that long and continuous ZnO-HNF with shell consisting of uniform compacted ZnO nanoparticles are successfully fabricated, and the shell thickness is approximately 30 nm. The formation mechanism of ZnO-HNF is speculated to be consequence of the different rate of mass diffusion during the annealing process (Kirkendall effect). The prepared Zn-HNF exhibits good performance in photocatalysis. The photocatalytic removal efficiency of Rhodamine B (RhB) under ultraviolet light irradiation can reach 94.08% in 1 hour, and the removal efficiency of Cr(VI) is 94.49% in 2 hours. This work provides new ideas for the development of ZnO in the field of photocatalysis, and provides new possibilities for more types of subsequent photocatalytic materials.

Rheological properties and sedimentation stability of magnetorheological fluid based on multi-walled carbon nanotubes/cobalt ferrite nanocomposites

In this investigation, nanocomposites of cobalt ferrite (CoFe2O4) nanoparticles grown on multi-walled carbon nanotubes (MWCNTs) were developed by a ultrasonic-assisted co-precipitation technique. The as-prepared MWCNTs/CoFe2O4 nanocomposites were characterized in detail using transmission electron microscope (TEM), Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectra, thermogravimetric analysis (TGA), superconducting quantum interference device (SQUID) magnetometer and nitrogen adsorption and desorption isotherms. The obtained MWCNTs/CoFe2O4 was adopted as the advanced dispersed phase for the fabrication of a uniform magnetorheological (MR) fluid, and its rheological properties and sedimentation stability were comprehensively examined. It had been revealed that the designed MR suspension exhibited typical MR features with increasing viscosity, shear stress, yield stress, storage modulus and loss modulus depending on the applied magnetic fields. It was worthy to note that the sedimentation stability of MR fluid was improved significantly, which was primarily attributed to the special three-dimensional network structure of MWCNTs/CoFe2O4 and the reduced density mismatch between the dispersed phase and carrier fluid.

The epoxy-tannic-modified crosslinked chitosan matrix with a selectively adsorptive activity towards charged proteins

Chitosan-based matrices have been proposed for the design of absorbents with target-selective activity, because they are easily modifiable, are cationic polyelectrolytes, and can be regenerated. In this study, chitosan monomers were folded into special three-dimensional structures by crosslinking them with epichlorohydrin and tannic acid. The introduction of active and charged groups such as epoxy and phenolic hydroxyl and synergistic effects among these groups produce chitosan matrices with differing abilities to adsorb proteins such as bovine serum albumin, ovalbumin, myoglobin, and lysozyme in an acidic environment. The adsorptive efficiency of proteins was evaluated via liquid chromatography. Bovine serum albumin and myoglobin were progressively adsorbed while ovalbumin was bound due to strong affinity and lysozyme was saturated in the initial stage. The protein selectivity was primarily dependent on molecular weight, molecular size, isoelectric point, and coulombic attraction. The study illustrated varying effectiveness of charged protein adsorption as well as different adsorption profiles.

Donor–acceptor conjugates-functionalized aluminum phthalocyanines: Photophysical and nonlinear optical properties

Photoinduced electron transfer/energy transfer (PET/ET) plays a very important role in improving the nonlinear optical (NLO) response. AlPc-Aqn and HAlPc-Aqn with donor-acceptor (D-A) structure were prepared by grafting aluminum phthalocyanine (AlPc) and hyperbranched aluminum phthalocyanine (HAlPc) through anthraquinone axial covalent bonding. After the axial covalent connection, the formed D-A phthalocyanine materials enhance the PET/ET process between the phthalocyanine ring and the anthraquinone structure, which results in significant fluorescence quenching and effectively improves the material's NLO properties. The discrepancy of LUMO levels (ΔE) further confirms that both AlPc-Aqn and HAlPc-Aqn formed a D-A system. This effectively promotes the electron transfer between the anthraquinone and the phthalocyanine ring, performing enhanced NLO response. Furthermore, compared to AlPc-Aqn, the special three-dimensional structure of HAlPc-Aqn brings a more efficient PET/ET process and exhibits a larger nonlinear absorption coefficient.