Friction heat-driven robust self-lubricity of -alkanols/epoxy resin coatings enabled by solid-liquid phase transition.

Due to the inherent damage effect, friction heat is commonly undesirable yet inevitable in moving components. Hence, obtaining robust running of mechanical assemblies under high sliding velocity is challenging. Herein, we report an alternative strategy to design robust self-healing lubricity materials by taking advantage of friction heat-driven solid-liquid phase transition employing facile coatings of -alkanols/epoxy resin.

Small molecular donor materials based on --bridged BODIPY dimers with a triphenylamine or carbazole unit for efficient organic solar cells.

Herein, we have designed and synthesized two novel BODIPY dimer-based small molecules, denoted as ZMH-1 and ZMH-2, covalently linked and functionalized with triphenylamine (TPA) (ZMH-1) and carbazole (C) (ZMH-2) units as the electron donor at the 3- and 5-positions of the BODIPY core, respectively. Their optical and electrochemical properties were investigated. We have fabricated all small molecule bulk heterojunction organic solar cells using these BODIPY-based small molecules as electron donors along with fullerene derivative (PCBM) and medium bandgap non-fullerene acceptor IDT-TC as electron acceptors.

State-of-the-art progresses for TiCT MXene reinforced polymer composites in corrosion and tribology aspects.

TiCT MXene, a revolutionary 2D material, has shown bright prospects in various fields, including energy conversion and storage, electronic devices, electromagnetic interference shielding, catalysis, biomedicine etc. The large specific surface area, high electrical conductivity, abundant surface terminations, and the highest stiffness among all solution-processed 2D materials of TiCT MXene make it a rising star in polymer composites. Not only have TiCT MXene-based polymer composites come into prominence in sensing, energy storage, and photothermal conversion fields as is widely known, but they have also shown great potential in corrosion and tribology fields.

Contact Characteristics and Tribological Properties of the Weaving Surface of Mn-Cu and Fe-Zn Damping Alloys.

In this paper, laser texturing is performed on the surface of Mn-Cu and Fe-Zn damping alloys and the tribological properties of the samples with various surface weaves under dry-sliding conditions are investigated. The results show that the surface weave parameters affect the size of the contact surface and change the number of micro-convex bodies at the contact interface. This leads to changes in the tangential damping of the contact and further affects the magnitude of the friction coefficient.

Amino-functionalized TiCT loading ZIF-8 nanocontainer@benzotriazole as multifunctional composite filler towards self-healing epoxy coating.

It is difficult for TiCT-containing epoxy coatings to prevent electrochemical corrosion at the metal/coating interface after long-term exposure to corrosive environments. Thus, endowing TiCT-containing epoxy coatings with self-healing function and good wear resistance is very significant. Here, a novel self-healing epoxy coating (f-TiCT-ZB@EP) is designed via incorporating with amino-functionalized TiCT loading 2-methylimidazole zinc salt (ZIF-8) nanocontainer@benzotriazole (f-TiCT-ZB) multifunctional composite filler, and its anti-corrosion and tribological properties are evaluated in detail.

Improving the Dynamic Mechanical Properties of XNBR Using ILs/KH550-Functionalized Multilayer Graphene.

Graphene has been considered an ideal nanoscale reinforced phase for preparing high-performance composites, but the poor compatibility and weak interfacial interaction with the matrix have limited its application. Here a highly effective and environmentally friendly method for the functionalization of graphene is proposed through an interaction between as-exfoliated graphene and (3-aminopropyl) triethoxysilane (KH550), in which 1-butylsulfonate-3-methylimidazolium bisulfate (BSOHMIm)(HSO) ionic-liquids-modified graphene was prepared via an electrochemical exfoliation of graphite in (BSOHMIm)(HSO) solution, then (BSOHMIm)(HSO)-modified graphene as a precursor was reacted with amine groups of KH550 for obtaining (BSOHMIm)(HSO)/KH550-functionalized graphene. The final products as filler into carboxylated acrylonitrile‒butadiene rubber (XNBR) improve the dynamic mechanical properties.

Effect of Hindered Phenol Crystallization on Properties of Organic Hybrid Damping Materials.

Organic hybrid damping materials have achieved sustainable development in recent years for superior damping properties due to the hydrogen bonding of hindered phenol. However, the aggregation and crystallization of hindered phenol in the matrix can lead to a sharp decline in material properties. Thus, a series of hindered phenol hybrid carboxylated nitrile rubber (XNBR) composites with different types and contents of hindered phenol were prepared by melt blending to study the effects of different hindered phenol on the properties of organic hybrid damping materials.

Investigation of the Microstructure and Mechanical Properties of Copper-Graphite Composites Reinforced with Single-Crystal α-Al₂O₃ Fibres by Hot Isostatic Pressing.

Single-crystal α-Al₂O₃ fibres can be utilized as a novel reinforcement in high-temperature composites owing to their high elastic modulus, chemical and thermal stability. Unlike non-oxide fibres and polycrystalline alumina fibres, high-temperature oxidation and polycrystalline particles boundary growth will not occur for single-crystal α-Al₂O₃ fibres. In this work, single-crystal α-Al₂O₃ whiskers and Al₂O₃ particles synergistic reinforced copper-graphite composites were fabricated by mechanical alloying and hot isostatic pressing techniques.

Modification of Talc@TiO toward high-performance nitrile rubber application.

To improve the dispersion of talcum powder (Talc) for polymer applications, modified nano-titania powders (TiO) using a silane coupling agent (KH550), a titanate coupling agent (NDZ201) and sodium polyacrylate (PAAS) were well adhered to the surface of Talc with a ball milling method, thereby preparing a series of mixed Talc@TiO particles to realize good dispersion in carboxylated acrylonitrile-butadiene rubber (XNBR). Note that Talc@TiO particles modified by PAAS and NDZ201 show better colloidal dispersion in anhydrous ethanol due to organification and repulsion of charge, with original Talc and NDZ201 modified Talc@TiO powders as a comparison. Modified Talc@TiO hybrid XNBR shows good performance characteristics, including damping capacity and impact resistance, depending mainly on the excellent mechanical property of Talc, good dispersion and the high adhesive force between modified Talc@TiO and XNBR.

Microstructure and Mechanical Properties of Graphene-Reinforced Titanium Matrix/Nano-Hydroxyapatite Nanocomposites.

Biomaterial composites made of titanium and hydroxyapatite (HA) powder are among the most important biomedicalmaterials due to their good mechanical properties and biocompatibility. In this work, graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites were prepared by vacuum hot-pressing sintering. The microstructure and mechanical properties of graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites with different graphene content were systematically investigated.

An enhanced low-frequency vibration ZnO nanorod-based tuning fork piezoelectric nanogenerator.

In this paper, a piezoelectric nanogenerator (PENG) based on a tuning fork-shaped cantilever was designed and fabricated, aiming at harvesting low frequency vibration energy in the environment. In the PENG, a tuning fork-shaped elastic beam combined with ZnO nanorods (NRs), instead of conventional rectangular cantilever beams, was adopted to extract vibration energy. Benefiting from the high flexibility and the controllable shape of the substrate, this PENG was extremely sensitive to vibration and can harvest weak vibration energy at a low frequency.

Synergetic Effect of Graphene and MWCNTs on Microstructure and Mechanical Properties of Cu/TiSiC/C Nanocomposites.

Multi-walled carbon nanotubes (MWCNTs) and graphenes have been taken for novel reinforcements due to their unique structure and performance. However, MWCNTs or graphenes reinforced copper matrix composites could not catch up with ideal value due to reinforcement dispersion in metal matrix, wettability to metal matrix, and composite material interface. Taking advantage of the superior properties of one-dimensional MWCNTs and two-dimensional graphenes, complementary performance and structure are constructed to create a high contact area between MWCNTs and graphenes to the Cu matrix.

Understanding hydration effects on mechanical and impacting properties of turtle shell.

Study of the properties of natural biomaterials provides a reliable experimental basis for the design of biomimetic materials. The mechanical properties and impact wear behaviors of turtle shell with different soaking time were investigated on a micro-amplitude impact wear tester. The damage behavior of turtle shells with different soaking time and impact cycles were systematically analyzed, also the impact dynamics behavior was inspected during the impact wear progress.

Space irradiation-induced damage to graphene films.

Graphene with impressive electrical, optical, chemical and mechanical properties has promising potential applications for photoelectric devices and mechanical components installed on the space facilities, which will probably face hostile environments including high-energy particulate irradiation. Here we explored the effect of simulated space irradiation on the structure and properties of large-area single-layer and multi-layer graphene films (about four layers) including atomic oxygen (AO), electron (EL) and proton (PR). AO with strong oxidizing capacity reacts with carbon atoms of graphene films and generates carbon dioxide, high-energy PR leads to polymorphic atomic defects in graphene through collision and excitation effects.

Enhanced performance of ZnO microballoon arrays for a triboelectric nanogenerator.

In recent years, triboelectric nanogenerators (TENGs), harvesting energy from the environment as a sustainable power source, have attracted great attention. Currently, many reports focus on the effect of surface modification on the electrical output performance of the TENG. In this work, we have fabricated vertically grown ZnO microballoon (ZnOMB) arrays on top of pyramid-featured PDMS patterned film, contacted with PTFE film to construct the TENG.

Self-Powered Safety Helmet Based on Hybridized Nanogenerator for Emergency.

The rapid development of Internet of Things and the related sensor technology requires sustainable power sources for their continuous operation. Scavenging and utilizing the ambient environmental energy could be a superior solution. Here, we report a self-powered helmet for emergency, which was powered by the energy converted from ambient mechanical vibration via a hybridized nanogenerator that consists of a triboelectric nanogenerator (TENG) and an electromagnetic generator (EMG).

Rotating-Disk-Based Hybridized Electromagnetic-Triboelectric Nanogenerator for Sustainably Powering Wireless Traffic Volume Sensors.

Wireless traffic volume detectors play a critical role for measuring the traffic-flow in a real-time for current Intelligent Traffic System. However, as a battery-operated electronic device, regularly replacing battery remains a great challenge, especially in the remote area and wide distribution. Here, we report a self-powered active wireless traffic volume sensor by using a rotating-disk-based hybridized nanogenerator of triboelectric nanogenerator and electromagnetic generator as the sustainable power source.

Green laser interferometric metrology system with sub-nanometer periodic nonlinearity.

This paper describes the design and realization of a heterodyne laser interferometer system that is applicable to metrology comparison. In this research, an iodine-stabilized Nd:YAG laser at 532 nm served as the light source. Two spatially separated beams with different offset frequencies are generated by two acousto-optic modulators to prevent any source mixing and polarization leakage.

Combined Effect of Textured Patterns and Graphene Flake Additives on Tribological Behavior under Boundary Lubrication.

A ball-on-plate wear test was employed to investigate the effectiveness of graphene (GP) nanoparticles dispersed in a synthetic-oil-based lubricant in reducing wear. The effect by area ratio of elliptically shaped dimple textures and elevated temperatures were also explored. Pure PAO4 based oil and a mixture of this oil with 0.

Lawn Structured Triboelectric Nanogenerators for Scavenging Sweeping Wind Energy on Rooftops.

A novel triboelectric nanogenerator (TENG) is designed, based on flexible and transparent vertical-strip arrays, for environmental wind-energy harvesting. Given the low cost, simple structure, and wide applicability, the TENGs present a green alternative to traditional methods used for large-scale wind-energy harvesting.

Investigation on the Tribological Behavior and Wear Mechanism of Five Different Veneering Porcelains.

Objectives: The primary aim of this research was to investigate the wear behavior and wear mechanism of five different veneering porcelains.

Methods: Five kinds of veneering porcelains were selected in this research. The surface microhardness of all the samples was measured with a microhardness tester.

Subnanometer absolute displacement measurement using a frequency comb referenced dual resonance tracking Fabry-Perot interferometer.

Fabry-Perot (F-P) interferometry is a traceable high-resolution method for displacement metrology that has no nonlinearity. Compared with the single resonance tracking F-P interferometry, the dual resonance tracking (DRT) F-P interferometer system is able to realize tens of millimeters measurement range while maintaining the intrinsic high resolution. A DRT F-P system is thus developed for absolute displacement measurement in metrology applications.

Note: Periodic error measurement in heterodyne interferometers using a subpicometer accuracy Fabry-Perot interferometer.

Periodic error is the major problem that limits the accuracy of heterodyne interferometry. A traceable system for periodic error measurement is developed based on a nonlinearity free Fabry-Perot (F-P) interferometer. The displacement accuracy of the F-P interferometer is 0.

UHMWPE carrying estradiol to treat the particle-induced osteolysis-Processing and characterizing.

The objective of this study was to explore the possibility of UHMWPE implant used as the drug carrier to treat particle-induced osteolysis. 17beta-estradiol (E2), which had the potential application on osteolysis treatment and the high melting point, was added into UHMWPE powder to produce UHMWPE-E2 composites through hot press processing. The hydrophobicity, crystallinity, mechanical properties, and wear performance of the UHMWPE-E2 were characterized compared with the control UHMWPE.

[Effect of erosion on strength of dental infiltrated Al2O3 ceramics].

The objective of the research is to investigate the elements of routine sandblast technique on the evolution of bending strength of dental infiltrated Al2O3 ceramics and the underlying erosion mechanism. The plane specimens of an infiltrated ceramic were manufactured, polished and then tested under the modified pen-like sandblasting apparatus (90 degrees erosive angle and 10 mm sandblasting distance), with different grit sizes, working pressure and disposing time. Half of samples were selected randomly and sintered subsequently with Vitadur alpha veneering porcelain.