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The purpose of this paper is to develop a potential nanoparticles lubricant additive for solving the problem of the insolubility and stable dispersity; the complex nanoparticles with core-shell structures are less studied in the field. Therefore, this paper determines novel complex nanoparticles and their tribological properties.

According to the conventional preparation method, the complex nanoparticle styrene/calcium borate (PS/O-CaB) was synthesized. The microstructures of the as-obtained samples were characterized by X-ray diffraction infrared spectroscopy and thermogravimetric analysis. Tribological properties of PS/O-CaB used as lubricating oil additive were evaluated on four-ball tribometer. The worn surface of the steel ball was investigated by a three-dimensional non-contact surface profilometer and X-ray photoelectron spectroscopy (XPS).

The results of the structure characteristic indicate two different crystalline forms, namely, Ca₂B₆O₁₁ and Ca₂B₂O₅, and the average size of calcium borate nanoparticles in PS/O-CaB is about 20-40 nm. Moreover, the good tribological properties are due to a wear resistance film containing both depositions and the tribochemical reaction products which comprise B2O3, FeB and Fe2O3.

Novel complex nanoparticles with core-shell structure (PS/O-CaB) were successfully prepared. Moreover, the PS/O-CaB shows excellent tribological capacity such as load-carrying, friction-reducing and antiwear property.

In order to obtain functionalized core-shell nanoparticles (CSNPs) as excellent toughening agents for epoxy resins. The paper aims to discuss these issues.

Functionalized CSNPs containing epoxy groups on the surface were synthesized by emulsion polymerization with butyl acrylate as the core and methyl methacrylate copolymerizing with glycidyl methacrylate (GMA) as the shell. CSNPs were used as toughening agents for epoxy resins and their chemical structure was characterized by FT-IR. The morphology of modified epoxy networks (MEPN) was analyzed by SEM and TEM. Both the mechanical properties and thermodynamic properties were studied.

The results show that nearly spherical CSNPs with the particle size of 50-100 nm are obtained. A certain amount of CSNPs are uniformly dispersed in epoxy resins by the grinding method and the MEPN shows the ductile fracture feature. The miscibility between CSNPs and epoxy matrix increases with the increase of GMA concentration which makes more bonds form between them. Epoxy resins toughened with 10 wt% CSNPs containing 10 wt% GMA show the best mechanical properties and the increase in tensile strength and impact strength of the MEPN is 13.5 and 59.7 percent, respectively, over the unmodified epoxy networks. And the improvement in impact strength is not accompanied with loss of thermal resistance.

The MEPN can be used as high-performance materials such as adhesives, sealants and matrixes of composites.

The functionalized CSNPs are novel and it can greatly increase the toughness of epoxy resins without loss of thermal resistance.

In this study, a highly sensitive and quantitative analysis method using surface-enhanced Raman scattering (SERS)-labeled immunoassay is adopted for bisphenol A bisphenol A (BPA) detection in water samples.

Primarily, an excellent SERS immuno-nanoprobe is prepared, which relays on Au/Ag core-shell nanoparticles tagged 4-mercaptobenzoic acid (4MBA) and labeled with specific antibody against BPA. Second, the coating antigen of 4,4-Bis(4-hydroxyphenol) valeric acid (BVA) coupling poly-L-lysine (PLL) conjugate (BVA-PLL) is fastened on the substrate. Based on competitive immunoassay, the antibody labeled on SERS immuno-nanoprobe will bind with the free BPA and BVA-PLL competitively.

A calibration curve was obtained by plotting the intensity of SERS signal of 4MBA at 1007 cm⁻¹ versus the concentration of BPA. The results indicated that the limit of detection (LOD) for BPA is 1 ng/mL and present a great capacity for higher sensitivity. Furthermore, the method was able to quantitatively detect BPA in water samples, which was validated by high performance liquid chromatography (HPLC).

The method was developed based on competitive immunoassay, and the conjugate (BVA-PLL) was chosen as the coating antigen. Au/Ag core-shell nanoparticles played as the SERS active substrate and were labeled with Raman reporter. The value of this paper is supplying a wide potential for analysis of target analytes in the environmental monitoring and food safety.

The purpose of this study is to prepare ZnFe₂O₄ nanospheres, sheet MoS₂ and three ZnFe₂O₄@MoS₂ core-shell composites with various shell thicknesses, and add them to the base oil for friction and wear tests to simulate the wear conditions of hybrid bearings.

Through the characterization and analysis of the morphology of wear scars and the elemental composition of friction films, the tribological behavior and wear mechanism of sample materials as lubricant additives were investigated and the effects of shell thickness and sample concentration on the tribological properties of core–shell composite lubricant additives were discussed.

The findings demonstrate that each of the five sample materials can, to varying degrees, enhance the lubricating qualities of the base oil and that the core–shell nanocomposite sample lubricant additive has superior lubricating properties to those of ZnFe₂O₄ and MoS₂ alone, among them ZnFe₂O₄@MoS₂-2 core–shell composites with moderate shell thickness performed most ideally. In addition, the optimal concentration of the ZnFe₂O₄@MoS₂ lubricant additive was 0.5 Wt.%, and a concentration that was too high led to particle deposition and affected the friction effect.

In this work, ZnFe₂O₄@MoS₂ core–shell composites were synthesized for the first time using ZnFe₂O₄ as the carrier and the lubrication mechanism of core–shell composites and single materials were compared and studied, which illustrated the advantages of core–shell composite lubricant additives. At the same time, the influence of different shell thicknesses on the lubricant additives of core–shell composites was studied.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-12-2022-0367/

This paper aims to introduce constructed CeO2/TiO2 core/shell nanoparticle as sensitive substance organic compounds.

The CeO₂ nanoparticles were synthesized by hydrothermal treatment. Then CeO₂/TiO₂ core/shell was fabricated by sol–gel method preparation of TiO₂ in the presence of ceria nanoparticles and applied as the sensitive material to make a sensor.

Formation of the nanoparticles was confirmed by X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM). The synthesized sensor exhibited not only good sensitivity to volatile organic compounds at room temperature but also logarithm of sensitivity versus concentrations was linear.

The sensor shows acceptable sensitivity to volatile organic compound at room temperature.

Experimental data revealed satisfactory reproducibility and short response and recovery times.

A radical mechanism for gas sensor reaction in two pathways was considered and activation energies were calculated by density functional theory (DFT) method to describe different sensitivities of tested volatile gases. The experimental results were consistent with the calculations.

This paper aims to propose a simple method for stabilizing silica-coated silver iodide (AgI/SiO₂) core-shell particles, of which a colloid solution functions as an X-ray contrast agent.

A colloid solution of AgI nanoparticles was prepared by mixing silver perchlorate and potassium iodide in water. The AgI/SiO₂ nanoparticles were fabricated by a sol-gel method using NaOH, H₂O and tetraethylorthosilicate in ethanol in the presence of AgI nanoparticles surface-modified with 3-mercaptopropyltrimethoxysilane.

The silica shells of AgI/SiO₂ particles were dissolved near the AgI nanoparticle surface, when they were washed by a process composed of centrifugation, removal of supernatant with decantation, addition of water as a washing solution and a shake with a vortex mixer. In contrast, the shells were not damaged by using ethanol as the washing solution, i.e. ethanol-washing. An X-ray photoelectron spectroscopy spectrum of the silica was changed after the ethanol-washing, which indicated that the ethanol-washing had an effect on the chemical bonds in silica. The effect also acted on the silica shells of AgI/SiO₂ particles, which did not damage the core-shell structure, i.e. controlled the dissolution of shell.

The paper demonstrates that the ethanol-washing is quite useful for stabilizing the core-shell structure composed of the silica shells.

The purpose of this paper is to investigate the tribological performance and mechanisms of BN/calcium borate nanocomposites (BCBNs) as additives in lubricating oil.

BCBNs were prepared by heterogeneous deposition method. And the morphology and structure of samples were analysed by transmission electron microscopy, Fourier transform infrared spectra and X-ray powder diffraction pattern. The maximum non-seizure load (PB) of samples was tested using four-ball friction tester. The average friction coefficients and wear tracks were obtained. In addition, tribological mechanism was also investigated using optical microscope, energy dispersive spectroscopy and X-ray photoelectron spectroscope.

It was found that the nanocomposites present core-shell nanostructure with the thickness of shell around 12 nm and the diameter of particles 100-200 nm, and tribological tests indicate that the PB value of BCBNs was increased by 113 per cent, whereas the average friction coefficient was decreased by 23.6 per cent and the bloom’s wear area was also decreased by 25.2 per cent.

This paper involves investigation on tribological properties and mechanism of the BCBNs with core-shell structure.

The purpose of this paper is to synthesize a kind of core-shell Ag@polyaniline (Ag@PAN) as a lubricant additive to improve the friction reduction and anti-wear abilities of lithium-based complex grease.

The core-shell Ag@PAN was prepared by a simple method and was introduced into the lithium-based complex grease. The typical properties of Ag@PAN were investigated by scanning electron microscopy (SEM), Fourier transforms infrared spectrometer and thermal gravimetric analyzer. The tribological properties were evaluated under different conditions. After the tribological test, the worn surface was analyzed by SEM and X-ray photoelectron spectroscopy to probe the lubrication mechanisms.

The prepared Ag@PAN could greatly improve the friction reduction and wear resistance of the friction pair under different conditions. The preferable tribological performances were mainly attributed to the synergism of various lubrication mechanisms including “mending effect,” “rolling effect” and lubricating protective film, and so on.

This study synthesizes a new kind of core-shell Ag@PAN as a lubricant additive, and it possesses preferable friction reduction and anti-wear abilities.

The purpose of this study is to synthesize a semiconductor photocatalyst which responds to both UV light and visible light in removal of organic dyes.

ZnO nanoparticles were pre-synthesised via sol-gel method using zinc nitrate tetrahydrate and methanamine at 90°C for 20 h. Subsequently, the as-synthesised ZnO nanoparticles were filtered, washed and dried. To synthesize ZnO-MnO₂ core shell nanocomposites (CSNs), 2:3 M ratio of KMnO₄ and MnSO₄ solution was stirred for an hour. Next, ZnO nanoparticles were added into the solution. The solution was heated at 160°C for 3 h for the formation of ZnO-MnO₂ CSNs. The structural, optical and photocatalytic properties of ZnO-MnO₂ CSNs were characterised by field emission scanning electron microscope, transmission electron microscopy (TEM), X-ray diffractometer and PL spectroscopy, respectively.

The photodegradation efficiencies of rhodamine B (RhB) dye by ZnO-MnO₂ CSNs as photocatalysts are 87.1 per cent under UV irradiation and 76.6 per cent under visible light irradiation, respectively. Their corresponding rate constants are 0.016 min⁻¹ under UV irradiation and 0.013 min⁻¹ under visible light irradiation. It can be concluded that N-deethylation was the dominant step during the photodegradation of RhB dye as compared to cycloreversion. The ZnO-MnO₂ CSNs demonstrated good photostability after three consecutive runs.

ZnO-MnO₂ CSN photocatalyst which could response to UV and visible light in degradation of RhB dye was synthesised using sol-gel method. The analysis shows that N-deethylation was the key photodegradation mechanism of RhB by ZnO-MnO₂ CSN.

The purpose of this paper is to synthesize MeO‐type pigments, focusing on the oxides containing zinc and magnesium.

Oxides ZnO and MgO were synthesized, their morphology was evaluated, and their impact on the physical properties of the paint film were assessed. A pigment of ZnO/core‐shell type also was synthesized. The physical‐chemical property of the synthesized pigments and the anticorrosion efficiencies of the paint films pigmented by them were determined. The binder used in the researched coatings was epoxy‐ester resin.

The shape of the particles was identified in the synthesized pigments. X‐ray diffraction analysis revealed the degree of precipitation and lattice parameters. All of the synthesized pigments had good anticorrosion efficiency in an epoxyester coating.

The synthesized pigments can be used conveniently in coatings protecting metal substrates against corrosion.

Of benefit is the fact that the synthesized pigments do not contain any environmentally harmful substances.