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Liquid metal represents a highly conductive and inherently deformable conductor for the development of stretchable electronics. The widespread implementations of liquid metal towards functional sensors and circuits are currently hindered by the lack of a facile and scalable patterning approach. In this study, we report a fully solution-based process to generate patterned features of the liquid metal conductor. The entire process is carried out under ambient conditions and is generally compatible with various elastomeric substrates. The as-prepared liquid metal feature exhibits high resolution (100 μm), excellent electrical conductivity (4.15 × 104S cm−1), ultrahigh stretchability (1000% tensile strain), and mechanical durability. The practical suitability is demonstrated by the heterogeneous integration of light-emitting diode (LED) chips with liquid metal interconnects for a stretchable and wearable LED array. The solution-based technique reported here is the enabler for the facile patterning of liquid metal features at low cost, which may find a broad range of applications in emerging fields of epidermal sensors, wearable heaters, advanced prosthetics, and soft robotics.

Using a simple, versatile, and flexible, low-cost, and high-efficient solvent knitting method, we report the synthesis of one-dimensional (1D) multiwalled carbon nanotube (MWCNT) based hyper-cross-linked polymers (HCPs). The composite materials combine the special 1D linear morphology and excellent mechanical properties of MWCNTs with high specific surface area and abundant pore structure characteristics of HCPs. Compared with pristine MWCNTs, the MWCNT-based HCPs exhibit higher surface area and significant enhancement in gas (such as CO

In this research, a multi-step spinning process was proposed to manufacture disc-like metallic parts with thick rim. The feasibility of this new process was validated by finite element (FE) simulation and forming experiment, while some undesirable geometries and defects including fold, pit, and underfilling were observed during each forming stage. To improve the forming quality, the effects of critical dimension parameters of rollers on the forming stability, streamline distribution, filling performance, and forming defects were systematically investigated by combination of FE and experimental analysis. The results showed that the dimension parameters of the roller significantly affect the forming stability and the streamline distribution, and the forming step has a remarkable effect on the filling performance. A circular slab with a diameter of 326 mm and a thickness of 3 mm was successfully formed into a defect-free disc-like part that has a thick rim with a width of 7.8 mm and thickness of 9.1 mm using the optimized parameters. This work presents a comprehensive understanding of the flow behavior and defects generation mechanism of the newly developed multi-step spinning process which can be used to manufacture large disc parts with thin web and thick rim.

Significant efforts have been devoted to develop efficient visible-light-driven photocatalysts for the conversion of CO2 to chemical fuels. The photocatalytic efficiency for this transformation largely depends on CO2 adsorption and diffusion. However, the CO2 adsorption on the surface of photocatalysts is generally low due to their low specific surface area and the lack of matched pores. Here we report a well-defined porous hypercrosslinked polymer-TiO2-graphene composite structure with relatively high surface area i.e., 988 m2 g−1 and CO2 uptake capacity i.e., 12.87 wt%. This composite shows high photocatalytic performance especially for CH4 production, i.e., 27.62 μmol g−1 h−1, under mild reaction conditions without the use of sacrificial reagents or precious metal co-catalysts. The enhanced CO2 reactivity can be ascribed to their improved CO2 adsorption and diffusion, visible-light absorption, and photo-generated charge separation efficiency. This strategy provides new insights into the combination of microporous organic polymers with photocatalysts for solar-to-fuel conversion.

Processable microporous organic polymers (MOPs) attract incomparable research interests becuase their vairous types such as monoliths and membranes are for practical application. Most of processable MOPs usually need the harsh conditions such as the use of expensive metal catalysts, specialized stereospecific monomers etc., which restrict the sustainable and real applications of processable MOPs. Therefore, the economical mass production of processable MOPs remains a formidable challenge. Herein, we report that a novel strategy for constructing processable hypercrosslinked polymers (HCPs) need two steps synthesis of pre-crosslinking and deep-crosslinking using divinylbenzene (DVB) as self-crosslinking monomer under the catalysis of a small amount of FeCl3 . The resulting HCPs monoliths possess high BET surface area of 1033-1056 m2 g-1 with hierarchical porosity, and show excellent mechanical strength up to 65 MPa. It is, to the best of our knowledge, the first report of using aromatic vinyl monomers as self-crosslinking monomers to generate HCPs monoliths with high surface area, yielding no by-products and high mechanical strength. This article is protected by copyright. All rights reserved.

Pitch, as a by-product of the petroleum and coal chemical industry, is in great need of improving its potential value by expanding its application areas. Using low-cost and available carbon precursors and facile preparation to design and prepare metal-free electrocatalysts with preeminent performance and high stability for oxygen reduction reaction (ORR) have become a research trend. Herein, we combine the above-mentioned requirements to prepare a kind of N-doped hierarchical porous carbon materials as ORR electrocatalysts using pitch-based hyper-cross-linked polymers (PHCPs) as carbon precursors by a simple ammonia activation process. Under the optimized pyrolysis temperature (900 °C), the optimal N-PHCP-900 owns high specific surface area of 999 m2 g−1, hierarchical pore structure, plentiful accessible active N and high density of defects. Benefitting from these special advantages, the N-PHCP-900 exhibits an outstanding ORR property with a positive half-wave potential (0.883 V vs. RHE) and robust durability in alkaline electrolyte, which surpass those for commercial Pt/C and the majority of non-noble metal electrocatalysts. Therefore, this work not only offers a novel paradigm in the development of affordable and efficient metal-free ORR electrocatalysts as the hopeful candidate, but also explores a feasible method for realizing the high value-added application of pitch.

Ablation behavior of C/C-ZrC-SiC composites was investigated using a plasma flame. The composites exhibited excellent ablation performance. After ablation for 180 s, three kinds of ablation behavior appeared from the border to the center on the surface, which were closely related to the temperature and denudation force. Additionally, the ablation behavior in the cross-sectional direction of the composites was mainly controlled by the temperature. During the ablation, ZrC and SiC were oxidized into ZrO 2 and SiO 2 , respectively, resulting in the formation of a ZrO 2 -SiO 2 binary eutectic system. The ablation mechanism was also discussed, which could provide strong illustration of the evolution processes of the eutectic system at different temperatures.

A simple synthetic method was developed to produce holey graphene with in-plane nanopores by a fast thermal expansion of graphene oxide (GO) in air and further thermal reduction in N 2 flow at 900 °C. The as-synthesized holey graphene nanosheets (HGN) shows meso-macroporous structure and higher surface area than chemically reduced graphene oxide (CRGO) by using hydrazine hydrate. The catalysts of HGN-900 supported Pt nanoparticles (Pt/HGN-900) were further prepared through in - situ chemical co-reduction and applied in the electro-oxidation of methanol. The electrocatalytic performance of catalysts was investigated by cyclic voltammetry (CV) and chronoamperometry (CA) analysis. The results indicate that the catalytic activity of Pt/HGN-10min-900 (377.5 mA mg −1 pt ) is bout 1.83 and 2.77 times higher than that of Pt/CRGO-900 (206.1 mA mg −1 pt ) and Pt/XC-72 (136.2 mA mg −1 pt ) catalysts in 0.5 mol L −1 H 2 SO 4 and 1.0 mol L −1 CH 3 OH, and Pt/HGN-900 catalysts show higher stable current density compared to that of Pt/XC-72 and Pt/CRGO-900 catalysts.

Here we choose a dihydronaphthyl-functionalized C60 fullerene as a building block and utilize a novel solvent knitting strategy based on Friedel–Crafts alkylation reaction to construct two kinds of novel porous materials by using dichloromethane (DCM) and 1,2-dichloroethane (DCE) as solvents and external crosslinkers. The resulting porous materials show relatively high apparent BET surface areas and gas uptake abilities.

A novel metalporphyrin-based microporous organic polymer (HUST-1-Co), which possesses a high surface area of 1360 m2 g−1 and a high CO2 uptake of 21.39 wt% (1 bar and 273 K) for CO2 capture and storage (CCS) and the efficient chemical conversion of CO2 under ambient conditions, is reported. This polymer incorporated both ultra-micropores and catalytic sites, and was synthesized by a novel solvent knitting hypercrosslinked polymers method, using 5,10,15,20-tetraphenylporphyrin (TPP) as the building block. The N2 sorption isotherms of the polymers show that HUST-1-Co possesses abundant ultra-micropores (centered at 0.68 nm), and a continuous mesoporous and macroporous structure, which not only enhances the interaction between the pore walls and CO2, but is also favourable for the catalysis process. The synergy of the ultra-micropores, abundant nitrogen atoms and Co2+ ions makes HUST-1-Co one of the highest CO2 uptake MOP materials reported so far and further endows it with efficient catalytic performance. HUST-1-Co is one of the most efficient catalysts for the coupling of CO2 with substituted epoxides with various functional groups at room temperature and atmospheric pressure, with an excellent recycling performance (more than 15 times). Moreover, the role of the mesoporous and macroporous structure of HUST-1-Co gives it a unique catalytic performance for different molecular sizes of epoxide substrates with excellent yields (>93%).

In this paper, we introduce an easy method for fabricating Si nanowires with nanodots using nanosphere lithography. First, a self-assembly ordered single layer of polystyrene nanospheres with a diameter of 220 nm was prepared on Si substrate. Secondly, the polystyrene spheres monolayer was etched by 02 with different time from 10 s to 35 s. After this etching process, the polystyrene nanowires between polystyrene spheres were fabrication. If the etching time was longer than 35 s, there were no polystyrene nanowires. Thereafter, the following etching process with carbon fluoride was performanced. The polystyrene nanowires and nanosphers were worked as masks. Finally, the Si nanowires with nanodots were formed. The size and morphology can be controlled by etching process. This technique for forming nanostructure arrays using nanosphere lithography can be applied in many areas of science and technology.

In this paper, a uniform PDDA-functionalized graphene composite film (GA–CS@PDDA-rGO) was utilized for detection of trace Hg2+ by using glutaraldehyde cross-linked chitosan (GA–CS) as a Hg2+-chelating adsorbent and film-forming agent. The results showed that a well-defined and high-sensitivity stripping peak at 0.06 V for Hg2+ was observed at the GA–CS@PDDA-rGO/GCE. Moreover, two important affecting factors of the content of PDDA-rGO and deposition potential were optimized on the GA–CS@PDDA-rGO/GCE modified electrode. Under the optimal conditions, the GA–CS@PDDA-rGO/GCE modified electrode showed a good linearity in the range of 0.03–5 μM between the concentration of the Hg2+ and stripping peak current. The detection limit was estimated to be 7.7 nM (S/N = 3). The interference and selectivity of other heavy metal ions were evaluated, showing no obvious interference on the Hg2+ detection. The results indicated that the GA–CS@PDDA-rGO composite film provided an efficient strategy and a new promising platform for detection of Hg2+.

Grinding parameters affect the morphology of a machined surface. Creep-feed face grinding with a cup wheel is a highly efficient and highly precise grinding method for the manufacturing of hard and brittle materials. There is a trade-off between the rate of material removal and machining precision because substantial material removal necessitates a deep grinding depth that usually results in poor surface quality. The problem of how to machine a high-quality surface while maintaining a high removal rate is therefore important in precision grinding. This paper first introduces this grinding method. Si3N4 is an important engineering ceramic widely used in many fields, and to improve its ground surface quality, an experimental design is established to investigate the relationship between the grinding depth in this method and the ground surface morphology. Making a non-contact optical measurement, the surface morphology is derived and then analyzed. First, surface roughness is investigated for different grinding depths, showing that depth does not affect the surface roughness because the end face of the cup wheel has a regrinding effect. Second, the power spectrum density is investigated, showing that the peaks and valleys of the surface morphology are distributed with increasing intensity as grinding depth increases. Third, the machined surfaces waviness is investigated, and is found to increase with the grinding depth. This is explained by the grinding force increasing with the depth, which intensifies the grinding machines vibration. This paper reveals an important characteristic of this method in that the grinding depth has little effect on the roughness of the ground surface.

Two kinds of POSS-based organic–inorganic hybrid porous materials have been synthesized via Friedel–Crafts and Scholl coupling reactions, for the first time, using low-cost building blocks i.e., octaphenylsilsesquioxanes and simple knitting approaches to obtain high Brunauer–Emmett–Teller (BET) surface area porous polyhedral oligomeric silsesquioxane (POSS)-based hybrid materials. N2 sorption isotherms of the polymers show that both these materials are predominantly microporous and mesoporous with BET surface areas of 795 m2 g−1 for the polymer of octaphenylsilsesquioxanes-1 (POPS-1) and 472 m2 g−1 for the polymer of octaphenylsilsesquioxanes-2 (POPS-2). Moreover, POPS-1 can reversibly adsorb 9.73 wt% CO2 (1 bar and 273 K) and 0.89 wt% H2 (1.13 bar and 77 K), and POPS-2 shows moderate gas uptake with 8.12 wt% CO2 (1 bar and 273 K) and 0.64 wt% H2 (1.13 bar and 77 K). In addition, the structural integrity of POSS based building blocks was completely preserved under relatively strong acidic conditions.

Novel layered microporous polymers with high surface area and gas storage were prepared by low-cost solvent knitting method., Two-dimensional (2D) nanomaterials, especially 2D organic nanomaterials with unprecedentedly diverse and controlled structure, have attracted decent scientific interest. Among the preparation strategies, the top-down approach is one of the considered low-cost and scalable strategies to obtain 2D organic nanomaterials. However, some factors of their layered counterparts limited the development and potential applications of 2D organic nanomaterials, such as type, stability, and strict synthetic conditions of layered counterparts. We report a class of layered solvent knitting hyper-cross-linked microporous polymers (SHCPs) prepared by improving Friedel-Crafts reaction and using dichloroalkane as an economical solvent, stable electrophilic reagent, and external cross-linker at low temperature, which could be used as layered counterparts to obtain previously unknown 2D SHCP nanosheets by method of ultrasonic-assisted solvent exfoliation. This efficient and low-cost strategy can produce previously unreported microporous organic polymers with layered structure and high surface area and gas storage capacity. The pore structure and surface area of these polymers can be controlled by tuning the chain length of the solvent, the molar ratio of AlCl3, and the size of monomers. Furthermore, we successfully obtain an unprecedentedly high–surface area HCP material (3002 m2 g−1), which shows decent gas storage capacity (4.82 mmol g−1 at 273 K and 1.00 bar for CO2; 12.40 mmol g−1 at 77.3 K and 1.13 bar for H2). This finding provides an opportunity for breaking the constraint of former knitting methods and opening up avenues for the design and synthesis of previously unknown layered HCP materials.

This paper presents a fundamental investigation of the system matching mechanisms involved in ultrasonic vibration assisted grinding (UAG) of titanium processing. The effects of system matching on grinding force and surface roughness are studied experimentally. The design of experiments and experimental equipment are described in detail. In this investigation, a five-variable four-level fractional factorial design is used to conduct experiments. The experiments are employed to reveal the main effects as well as the interaction effects of the ultrasonic parameters on the process outputs such as material removal rate (MRR), grinding force, surface topography and surface roughness. Experimental results showing that the application of system matching in UAG can improve the work piece grinding quality.

An electrochemical sensor based on graphene and gold nanoparticles has been developed for the detection of trace Cu 2+ with the anodic stripping voltammetry analysis. The Au-GR/GCE electrode was constructed by the electrophoretic deposition and electrochemical reduction of graphene oxide on GCE electrode, followed by the electrochemical deposition of AuNPs on the GR/GCE electrode. The morphology, structure and electrochemical performance of chemically modified electrodes are characterized by SEM, AFM, cyclic voltammetry and Electrochemical Impedance Spectroscopy. Differential pulse voltammetry was employed for evaluating detection of trace Cu 2+ through the accumulation process. Under the optimum experimental conditions, the Au-GR/GCE electrode exhibited excellent stripping response of Cu 2+ and the stripping peak currents linearly increased with the increasing concentration of Cu 2+ . The limit of detection was estimated to be 0.028 nM ( S / N = 3).

According to anisotropic and inhomogeneous structure of fiber-reinforced ceramic matrix composites (FRCMC), it is difficult to control the surface quality with the traditional method used in metal material. The present paper studies the influence of diamond wheel grinding process on surface micro-topography and properties of SiO 2 /SiO 2 composite. The research is based on some new discovery that the material enhanced fiber orientations play a key role in micro-topography of FRCMC grinding surface. Through a series of experiments, we investigate the relationship between grinding process and the quality of composites surface. We also analyze characteristics of the material surface topography height, wave distribution and surface support properties in details. This paper employs the orthogonal design to optimize grinding process parameters and also successfully models a critical condition to modify the surface characteristics. The results show that speed of grinding wheel has the greatest influence on height and surface support properties, the next is grain mesh size and depth of cut. The grain mesh size is the key factor for surface micro-topography modification. Compared to the surface with woven texture, the modified surface has better symmetrical characteristic. The research obtained will be an important technical support on improving the processing quality of FRCMC.

Ultrasonic vibration assisted grinding (UAG) is an effective processing method for hard and brittle materials. Compared with common grinding (CG), both of grinding force and workpiece surface quality is improved by UAG, but the principle of improvement is still unclear. In order to reveal the mechanism of grinding force reduction and grinding quality improvement in UAG, this paper presents a mathematical model for system matching in UAG of brittle materials. Assuming that brittle fracture is the primary mechanism of material removal in UAG of brittle materials, the system matching model is developed step by step. On the basis of this mathematical model, the mechanism of grinding force reduction and surface roughness forming are discussed. The advantage of UAG processing brittle materials is pointed out in theory. Using the model developed, influences of input variables on grinding force are predicted. These predicted influences are compared with those determined experimentally. This model can serve as a useful foundation for development of grinding force models in UAG of brittle materials and models to predict surface roughness in UAG.

Porous organic polymers (POPs) have enormous applications in various fields and thus have received a lot of research attention in recent decades. Numerous synthetic methods have been developed, but mild synthesis conditions and fast polymerization rate are highly desired. Herein, high porous POPs with high surface areas from aromatic vinyl monomers by using acid catalysis method is reported. The polymerization is ultrafast and could be accomplished even in 5 min at room temperature. Furthermore, the surface area can be tuned by using various acid catalysts and controlling the reaction time. Due to the high surface area, these POPs show promising adsorption of carbon dioxide and hydrogen, respectively. Furthermore, the large π-system of the building block and high surface area of the POPs also make them show potential applications in photocatalytic hydrogen evolution as well as promising catalyst support for metal nanoparticles.

The synthesis of highly crystalline covalent triazine frameworks (CTFs) with ultrastrong covalent bonds (aromatic CN) from the triazine linkage presents a great challenge to synthetic chemists. Herein, the synthesis of highly crystalline CTFs via directly controlling the monomer feeding rate is reported. By tuning the feeding rate of monomers, the crystallization process can be readily governed in a controlled manner in an open system. The sample of CTF-HUST-HC1 with abundant exposed {001} crystal facets has the better crystallinity and thus is selected to study the effect of high crystallinity on photoelectric properties. Owing to the better separation of photogenerated electron-hole pairs and charge transfer, the obtained highly ordered CTF-HUST-HC1 has superior performance in the photocatalytic removal of nitric oxide (NO) than its lesser crystalline counterparts and g-C3 N4 .

Amphiphilic hemi-telechelic and telechelic poly(ethylene oxide) (PEO) hybrids based on polyhedral oligmeric silsesquioxane (POSS) were prepared via the copper-catalyzed azide–alkyne “click” reaction. Thermal properties of POSS–PEO were characterized using differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The result shows that the thermal properties of telechelic POSS–PEO are effectively enhanced by POSS. The morphology of the POSS-containing PEO hybrid crystals was investigated using polarized optical microscopy (POM), and the results indicate that it is much easier for the POSS in the telechelic POSS–PEO hybrids (T-POSS–PEO) to form quite large aggregates, which act as nucleating agents during the crystallization of the PEO chains. The self-assembly behavior of POSS–PEO in water was also studied using transmission electron microscopy (TEM). The results reveal that hemi-telechelic POSS–PEO hybrids (HT-POSS–PEO) can self-assemble into spherical aggregates, whereas the T-POSS–PEO hybrids self-assemble into ellipsoidal aggregates.

The star-shaped organic/inorganic hybrid poly( l -lactide) (PLLA) based on polyhedral oligomeric silsesquioxane (POSS) was prepared using octa(3-hydroxypropyl) polyhedral oligomeric silsesquioxane as initiator via ring-opening polymerization (ROP) of l -lactide (LLA). The molecular weight of POSS-containing star-shaped hybrid PLLA (POSSPLLA) can be well controlled by the feed ratio of LLA to initiator. The POSSPLLA was further functionalized into the macromolecular reversible addition-fragmentation transfer (RAFT) agent for the polymerization of N -isopropylacrylamide (NIPAM), leading to the POSS-containing star-shaped organic/inorganic hybrid amphiphilic block copolymers, poly( l -lactide)– block –poly( N -isopropylacrylamide) (POSS(PLLA– b –PNIPAM)). The self-assembly behavior of POSS(PLLA– b –PNIPAM) block copolymers in aqueous solution was investigated by dynamic light scattering (DLS), transmission electron microscopy (TEM) and atomic force microscopy (AFM). DLS showed the PNIPAM block in the aggregates is temperature-responsive and its phase-transition is reversible. TEM proved that the star-shaped POSS(PLLA– b –PNIPAM) amphiphilic block copolymers can self-assemble into the vesicles in aqueous solution. The vesicular wall and coronas are composed of the hydrophobic POSS core and PLLA, and hydrophilic PNIPAM blocks, respectively. Therefore, POSSPLLA and POSS(PLLA– b –PNIPAM) block copolymers, as a class of novel organic–inorganic hybrid materials with the advantageous properties, can be potentially used in biological and medical fields.

Although submicrometer dust of 0.01-1 ?m is a great hazard to the human being and the environment, the collection efficiency of which by using an electrostatic precipitator is still low at present. The high density ions (1.97 × 109 cm-3), which are produced by the synergistic effect of the high gas particle momentum of 9.82 × 10-22 g ·m ·s-1 in the flue and ionized in the strong electric field, provide many ions for submicrometer dust charging and coagulation. In this paper, the new method of homopolarity submicrometer dust coagulation in an alternating electric field was investigated. The experimental results showed that in the conditions of reduced alternating electric field strength of 7 Td and frequency of 100 Hz, for a median particle size of 0.2-?m silicon powder, the mass percent of particles of < 0.2 ?m decreased from 71% to 53%. The changing rate was 25.4%, whereas the mass changing rate of the particles of 5-10 ?m increased by 1.62 times. For a median particle size of 6-?m talcum powder, the mass percent of particles of < 0.2 ?m decreased from 22% to 11%. The changing rate was 50%, whereas particles of 5-10 ?m increased by 18%. The experimental results showed that the coagulation in an alternating electric field will be an effective method to collect submicrometer dust in high velocity flow field.

In this paper, the enhanced photoluminescence from CdS thin film with SiO2 nanopillar array (NPA) was demonstrated. The CdS was prepared using chemical bath deposition in a solution bath containing CdSO4, SC(NH2)2 and NH4OH. The SiO2 NPA was fabricated by the nanosphere lithography (NSL) techniques. The nanopillar is about 50 nm in diameter and the height is 150 nm. As a result, the sample with NPA shows an obvious improvement of photoluminescence (PL), compared with the one without NPA. In addition, we also observed that the PL intensity is increased ~5 times if the active layer is deposited on the nanopillar arrays and covered by a thin metal film of Al. It is noteworthy that the enhancement of photoluminescence could be attributed to the roughness of the surface, the 2D photonic band gap (PBG) effect and the surface plasmon resonance (SPR) effects.

Fiber-reinforced ceramic matrix composites (FRCMCs) have potential applications in aerospace and other high-tech fields. Meanwhile, it is significant to evaluate the grinding surface quality of FRCMCs. But according to FRCMCs’ anisotropic and non-homogeneous structure, it is difficult to evaluatethe surface quality with the traditionalmeasuring method used in metal material. The present paper studied the 3D micro-topographical measurement and evaluationfrom a new perspective. The research is based on some new discovery that the material enhanced fiber orientation played key role in micro-topographical of FRCMC grinding surface. Using a non-contact optical measurement instrument, the method was developed on 2.5D SiO2/SiO2 composite. Through a series of measuring experiments, we found that both starting position of measurement and sampling conditions affected on the measurement results. This paper recommendedoptimization measurement parameter valuesof sampling conditions, and also analyzedcharacteristics of the RCMC grinding surface topography on amplitude, wave distribution and surface supportcharacteristics in details. The results show that the optimal range of sampling interval is 40 μm to 70 μm, the range of sampling area is better more than 64mm2 and the range of sampling speed is 8 to 14mm/s. The measurement of surface topography is the bridge framed between the manufacture and parts performance, so theresearchobtained will be an important technical support on improvingthe processing quality of FRCMC.