- 标题
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- 实验方案
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[Polymers and Polymeric Composites: A Reference Series] Functional Polymers || Organic-Inorganic Hybrid Materials and Their Applications
摘要： The organic-inorganic composites in addition to providing new alternate materials represent a class that exhibit novel, astonishing features, and their properties can be tailored to suit a particular application. These are developed by combinations of two or more materials that differ in form or composition on a macroscale. The matrix and the filler are two indispensable components of a composite. In this chapter, synthetic routes, viz., sol-gel, blending, and emulsion polymerization, classification, and application of organic-inorganic composites as ion-selective membrane electrodes has been discussed. The ion-selective electrodes provide simple, reliable, low cost, on-spot methods for the detection of heavy metal ions. The field of hybrid materials is vast open and promising and newer possibilities to improve their application are to be explored.
关键词： Selectivity,Sol-gel synthesis,Composite,Ion-selective membrane electrode
更新于2025-09-09 09:28:46
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Influence of Sm and Nb on the structural, electric, magnetic and magneto-electric properties of BaTiO3-Li0.5Fe2.5O4 composite ceramics grown by the conventional solid state technique
摘要： The Sm and Nb doped BaTiO3-Li0.5Fe2.5O4 composite ceramics having chemical formulae (90)BaTi(1?2x)NbxSmxO3 + (10) Li0.5Fe2.5O4 (x = 0, 0.05 and 0.1) were synthesized using conventional solid state technique. The structural, morphological, magnetic, dielectric, ferroelectric and magneto-electric properties of composites have been studied. The XRD measurement reveals the absence of peaks pertaining to impurities and strongly confirms the high crystalline nature of all the composites. From FESEM images, the average grain size of composites increases with increase in the concentration of Nb and Sm. The VSM studies confirm the soft magnetic nature of all the composites. The dielectric measurements confirm the increase in the transition temperature (Tc) of the BTL composite with an increase in the concentration of Nb and Sm. The P–E studies confirm that the ferroelectric nature of the BTL composite softens after doping Nb and Sm in it. The ME voltage coefficient value confirms the uniform growth of grains in all the composites and reveals a strong interaction between ferroelectric and magnetic orders.
关键词： magneto-electric properties,BaTiO3-Li0.5Fe2.5O4,electric properties,magnetic properties,composite ceramics,Sm and Nb doping,structural properties
更新于2025-09-09 09:28:46
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A Fast and Efficient Method for the Composite Scattering of a Coated Object Above 3D Random Rough Surfaces
摘要： This paper presents a fast and ef?cient method that combines physical optics with physical optics to solve the composite scattering problem of a coated object above 3-D random rough surfaces. The object coated with lossy electric or magnetic radar absorbing materials is modeled as a strati?ed structure, and 3-D random rough surfaces are generated using Monte Carlo method with Gaussian spectrum. The proposed method utilizes fast and ef?cient physical optics as a solution for the coated object and the underlying random rough surface. Then a reradiation physical optics method based on Huyghens’ principle is used as a solution for coupling scattering between the coated object and the underlying rough surface. The proposed method is numerically validated by comparing it with the commercial software FEKO and a multihybrid Kirchhoff approximation with the hybrid ?nite element-boundary integral algorithm. Runtime and memory consumption are also compared. Our method is found to reduce considerable time and memory while maintaining suf?cient accuracy. The difference scattering radar cross section of a coated sphere above a 3-D perfectly electric conductor rough surface is numerically simulated. Furthermore, the dependence of difference scattering characteristic on the object coating parameters and the underlying rough surface parameters under different polarizations is discussed.
关键词： coating object,rough surface,Composite scattering
更新于2025-09-09 09:28:46
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Cooperative effect between BaTiO3 and CaFe2O4 in a cocatalyst-free heterojunction composite for improved photochemical H2 generation
摘要： A series of novel BaTiO3/CaFe2O4 heterojunction composites with different weight ratios of CaFe2O4 vs BaTiO3 was successfully fabricated by sonication-calcination method using the pre-prepared BaTiO3 and CaFe2O4 powders synthesized in hydrothermal and sol-gel methods, respectively. The composites were well characterized using XRD, UVevis DRS, SEM, TEM, EDS and XPS to substantiate that BaTiO3 and CaFe2O4 coexist in the heterojunction composite. The highest photocatalytic hydrogen generation rate was obtained for BaTiO3/CaFe2O4 (40 wt%) compared to either of its individual counterparts and this improvement indicated the existence of a cooperative effect between BaTiO3 and CaFe2O4 in the heterojunction. Based on UV-vis-DRS, photoluminescence and time-resolved fluorescence lifetime measurements, the cooperative effect between BaTiO3 and CaFe2O4 originated from the improved photoresponse in the visible light region and efficient separation of the photogenerated electronehole pairs augmenting their availability for the photocatalytic reaction. A plausible photocatalytic mechanism was also deduced using electrochemical impedance spectroscopy measurements, describing the migration direction of the separated charge carriers. Moreover, the best composite BaTiO3/CaFe2O4 (40 wt %) exhibited fairly stable photoactivity for H2 production using the sacrificial agent (Na2S and Na2SO3) without the assistance of any noble metals as cocatalysts.
关键词： Cocatalyst free,BaTiO3/CaFe2O4 composite,Hydrogen evolution,Sonication-calcination method,Heterojunction
更新于2025-09-09 09:28:46
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[ASME ASME 2018 Conference on Smart Materials, Adaptive Structures and Intelligent Systems - San Antonio, Texas, USA (Monday 10 September 2018)] Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation, and Control of Adaptive Systems; Integrated System Design and Implementation - Simulation of a Composite Piezoelectric and Glass Fiber Reinforced Polymer Beam for Adaptive Stiffness Applications
摘要： Glass Fiber Reinforced Polymer (GFRP) beams have shown over a 20% decrease in weight compared to more traditional materials without affecting system performance or fatigue life. These beams are being studied for use in automobile leaf-spring suspension systems to reduce the overall weight of the car therefore increasing fuel efficiency. These systems are subject to large amplitude mechanical vibrations at relatively constant frequencies, making them an ideal location for potential energy scavenging applications. This study analyses the effect on performance of GFRP beams by substituting various composite layers with piezoelectric fiber layers and the results on deflection and stiffness. Maximum deflection and stress in the beam is calculated for varying the piezoelectric fiber layer within the beam. Initial simulations of a simply supported multimorph beam were carried out in ABAQUS/CAE. The beam was designed with symmetric piezoelectric layers sandwiching a layer of S2-glass fiber reinforced polymer and modeled after traditional mono leaf-spring suspension designs with total dimensions 1480 x 72 x 37 mm3, with 27 mm camber. Both piezoelectric and GFRP layers had the same dimensions and initially were assumed to have non-directional bulk behavior. The loading of the beam was chosen to resemble loading of a leaf spring, corresponding to the stresses required to cycle the leaf at a stress ratio between R = 0.2 and 0.4, common values in heavy-duty suspension fatigue analysis. The maximum stresses accounted for are based on the monotonic load required to set the bottom leaf surface under tension. These results were then used in a fiber orientation optimization algorithm in Matlab. Analysis was conducted on a general stacking sequence [0°/45°]s, and stress distributions for cross ply [0°/90°]s, and angle ply [+45°/-45°]s were examined. Fiber orientation was optimized for both the glass fiber reinforced polymer layer to maximize stiffness, and the piezoelectric fiber layers to simultaneously minimize the effect on stiffness while minimizing deflection. Likewise, these fibers could be activated through the application of electric field to increase or decrease the stiffness of the beam. The optimal fiber orientation was then imported back into the ABAQUS/CAE model for a refined simulation taking into account the effects of fiber orientation on each layer.
关键词： adaptive stiffness,composite beams,Glass Fiber Reinforced Polymer,energy scavenging,piezoelectric
更新于2025-09-09 09:28:46
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TiO2@g-C3N4 heterojunction with directional charge migration behavior for photodegradation of tetracycline antibiotics
摘要： The performance of semiconductor photocatalysts in organic contaminants degradation is strongly influenced by the structure-related charge separation behavior. Hence, titanium dioxide (TiO2) nanowire, which is efficient in directional migration of photocarriers, is prepared and employed as the carrier for the in situ growth of discrete graphite carbon nitride (g-C3N4) to form a compact and high-reactive heterojunction photocatalyst. The structures and properties of the samples are systematically characterized and discussed. The experimental results indicate that the tetracycline photodegradation efficiency obtained by employing TiO2@g-C3N4 as the photocatalyst is improved by 126% and 75%, respectively, compared to that using TiO2 nanowire and bulk g-C3N4. This work highlights that precisely controlling the microstructure and charge separation behavior is critical for preparing high-reactive photocatalysts.
关键词： Composite materials,Semiconductors,Heterojunction,g-C3N4,Photocatalysis
更新于2025-09-09 09:28:46
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Computational investigation of arranged scintillating particle composites for fast neutron detection
摘要： Composite materials have the potential to play an important role in enabling high-performance and cost-effective neutron detectors for fundamental science, global security, and dosimetry applications. This study presents neutron and gamma transport simulation results on composites consisting of 6Li-containing GS20 scintillator glass particles arranged in an organic matrix. These composites achieve high sensitivity for neutrons while suppressing signals from gamma rays. The simulations successfully identified optimal composite parameters such as particle size, geometry, and inter-particle pitch. This information is key to the subsequent fabrication and scale-up of the desired GS20-in-acrylic composite. The simulation results presented in this paper demonstrate that arranged composites can provide high neutron detection efficiency with gamma misidentification values of <1 in 106 gamma rays, assuming irradiation with a 252Cf spontaneous fission source.
关键词： Scintillator particle,Fast and thermal neutron detection,Lithium-6,Composite
更新于2025-09-09 09:28:46
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Pyrite-Type CoS2 Nanoparticles Supported on Nitrogen-Doped Graphene for Enhanced Water Splitting
摘要： It is extremely meaningful to develop cheap, highly efficient, and stable bifunctional electrocatalysts for both hydrogen and oxygen evolution reactions (HER and OER) to promote large-scale application of water splitting technology. Herein, we reported the preparation of CoS2 nanoparticles supported on nitrogen-doped graphene (CoS2@N-GN) by one-step hydrothermal method and the enhanced electrochemical efficacy for catalyzing hydrogen and oxygen in water electrolysis. The CoS2@N-GN composites are composed of nitrogen-doped graphene and CoS2 nanocrystals with the average size of 73.5 nm. Benefitting from the improved electronic transfer and synergistic effect, the as-prepared CoS2@N-GN exhibits remarkable OER and HER performance in 1.0 M KOH, with overpotentials of 243 mV for OER and 204 mV for HER at 10 mA cm?2, and the corresponding Tafel slopes of 51.8 and 108 mV dec?1, respectively. Otherwise, the CoS2@N-GN hybrid also presents superior long-term catalytic durability. Moreover, an alkaline water splitting device assembled by CoS2@N-GN as both anode and cathode can achieve a low cell voltage of 1.53 V at 60 ?C with a high faraday efficiency of 100% for overall water splitting. The tremendously enhanced electrochemical behaviors arise from favorable factors including small sized, homogenously dispersed novel CoS2 nanocrystals and coupling interaction with the underlying conductive nitrogen-doped graphene, which would provide insight into the rational design of transition metal chalcogenides for highly efficient and durable hydrogen and oxygen-involved electrocatalysis.
关键词： water splitting,HER/OER,graphene,nanoparticle,composite,cobalt sulfide
更新于2025-09-09 09:28:46
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TiO2-SiO2-PMMA Terpolymer Floating Device for the Photocatalytic Remediation of Water and Gas Phase Pollutants
摘要： Floating photocatalytic devices are highly sought-after as they represent good candidates for practical application in pollutant remediation of large water basins. Here, we present a multilayer floating device for the photocatalytic remediation of contaminants present in water as well as of volatile species close to the water surface. The device was prepared on a novel tailored ter-polymer substrate based on methylmethacrylate, α-methylstyrene and perfluoroctyl methacrylate. The ad hoc synthesized support presents optimal characteristics in terms of buoyancy, transparency, gas permeability, mechanical, UV and thermal stability. The adhesion of the TiO2 top layer was favoured by the adopted casting procedure, followed by a corona pre-treatment and by the deposition of an intermediate SiO2 layer, the latter aimed also at protecting the polymer support from photocatalytic oxidation. The device was characterized by contact angle measurement, UV-vis transmittance and scanning electron microscopy. The final device was tested for the photocatalytic degradation of an emerging water pollutant as well as of vapors of a model volatile organic compound. Relevant activity was observed also under simulated solar irradiation and the device showed good stability and recyclability, prospecting its use for the photocatalytic degradation of pollutants in large water basins.
关键词： titanium dioxide,tetracycline,ethanol,composite,photocatalytic oxidation,polymethylmethacrylate
更新于2025-09-09 09:28:46
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Photocatalytic Activity and Humidity Sensor Studies of Magnetically Reusable FeWO <sub/>4</sub> –WO <sub/>3</sub> Composite Nanoparticles
摘要： Different mole ratios of (8:2, 6:4, 4:6 and 2:8) iron tungstate–tungsten trioxide (FeWO4–WO3) composite nanoparticles were synthesized by solid state method. The synthesized composite nanoparticles were characterized by powder X-ray diffraction analysis (XRD), field-emission scanning electron microscopy (FE-SEM) with energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) studies. The crystalline nature and particle size of the samples were characterized by powder X-ray diffraction analysis (XRD). The morphology was confirmed by field-emission scanning electron microscopy (FE-SEM) analysis and transmission electron microscope (TEM). The energy dispersive X-ray spectroscopy (EDX) proved the purity of nanocomposites. Vibrating sample magnetometer reveals that the sample shows paramagnetic property based on the metal present in the prepared nanocomposites at room temperature. The magnetic property is due to the structural defects rather than the impurity phase. Magnetization saturation value (Ms = 398.7 emu/g) of FWWO-46 composite nanoparticles is high enough to be magnetically removed by applying a magnetic field. The composites were subjected to DC conductance measurement as a function of relative humidity in the range of 5–98%, achieved by different water vapour buffers thermostated at room temperature. The sensitivity factor, Sf = R5%/R98%, where R5% and R98% the values of the resistances measured at different RH respectively, are evaluated in Table I. If the composite has the greater value of Sf, then those materials possess the greater sensitivity towards moisture. The sensitivity factor (Sf) of the prepared composite nanoparticles was FWWO-10 (473), FWWO-82 (209), FWWO-64 (323), FWWO-46 (3956), FWWO-28 (361) and FWWO-01 (373). From this experimental value FWWO-46 exhibit the maximum Sf value of 3956 among the composites. This was due to the presence of more pores and cavities in the morphology of FWWO-46 then the other composite nanoparticles. Meanwhile the composite FWWO-46 can interact with water molecules easily then the others. The absorption and desorption of water molecules vary from the other composites. In the presence of water molecules on the morphology of FWWO-46 shows higher conductivity and higher sensitivity factor (Sf). At low relative humidity, water adsorption on the surface of the sample was likely the dominant factor for electronic conduction. The adsorbed water increases the surface electrical conductivity of the ceramic due to the increased charge carrier, protons in the ceramic/water system. The conductivity was further increased by the presence of pores on the sample surface. In the initial stage of water adsorption, a few water vapour molecules chemisorbed on the grain surface by a dissociative mechanism to form two surface hydroxyls per water molecule. In this chemisorbed layer charge transport occurs by the hopping mechanism. Conduction probably occurs by the Grotthus transport mechanism.
关键词： Composite,Photocatalytic Activity,Iron Tungstate,VSM,Humidity Sensors,Tungsten Trioxide
更新于2025-09-09 09:28:46