Excellent Thermal Conductivity Research Articles

High efficiency photothermal synergistic degradation of toluene achieved through the utilization of a nickel foam loaded Pt-CeO2 monolithic catalyst

Recent research highlights the pressing need for innovative and practical oxidation degradation technologies for volatile organic compounds (VOCs). In this study, a monolithic catalyst was successfully developed by loading Pt-CeO2 onto nickel foam (NF) matrix through hydrothermal and reduction methods. The photothermal catalytic performance was investigated at room temperature for varying Pt content, toluene concentration, light source type, and water content. Remarkably, the toluene removal efficiency and CO2 selectivity stabilized at 98.8 % and 74.6 %, respectively, within less than 10 min of light activation. The d-d transition thermal effect of CeO2 and plasma effect of Pt enhanced light-to-heat conversion and active free radical generation (•O2– and •OH) through light absorption, respectively. The NF matrix's excellent thermal conductivity ensured a rapid increase in catalyst temperature upon visible light irradiation, reaching 173 °C. The study demonstrated that both the Mars-van Krevelen (Mvk) oxidation process, driven by temperature increase from near-infrared (NIR) absorption, and the free radical oxidation process, induced by higher energy illumination, synergistically contributed to toluene decomposition and mineralization. The catalyst's morphology, physical and chemical properties, surface synergistic oxidation process involving gaseous oxygen and free radicals, and toluene degradation pathway were thoroughly analyzed. We believe that this coexistence of thermocatalytic and photocatalytic mechanisms in a monolithic catalyst driven by renewable solar energy holds significant potential for practical applications and warrants further exploration.

Fabrication of a twisted sensing yarn for multifunctional wearable applications

Nanofibers are ideal for the fabrication of fiber-based sensors owing to the wide applicability of such sensors in various fields. However, achieving high sensitivity and excellent tensile properties while maintaining high electrical conductivity in such sensors is difficult. This study proposes a simple fabrication method for a helical conductive yarn, core–sheath helical yarn (CSHY), in which the electrospun thermoplastic polyurethane (TPU) /boron nitride (BN) film is used as the fibrous material and coated with a liquid metal (LM), EGaIn. The fiber is then stretched and twisted to obtain the CSHY with high sensitivity, tensile stability, and durability as well as fast response and recovery. Experimental results show that the sensor fabricated by weaving the CSHY has a water contact angle of 143.2°, indicating that it can be used for human motion monitoring and underwater applications. In addition, the LM has excellent electrical conductivity and thermal conductivity and exhibits a synergistic effect with BN that is uniformly arranged along the fiber length. Thus, the fabric-based sensor exhibits excellent heat-dissipation, temperature-sensing, and electric-heating performances. Consequently, the proposed multifunctional smart yarn exhibits excellent strain sensing, self-controlled thermal management, and hydrophobic performance, with potential applications in future wearable electronics.

Universal high-performance bulk graphites from natural flake graphite by rapid sintering

High performance graphites (HPGs) are a key material in modem industries; however, prevailing HPGs are short of comprehensive properties in many aspects, i.e., a specific property of HPGs is always achieved at the cost of other properties. And the production of HPGs is highly costly and causes severe environmental problems. Current HPGs are derived from various carbonaceous precursors, excluding nature flake graphite (NFG), the best graphite source. Typically, NFG-based bulk graphite has poor mechanical properties because NFG is difficult to sinter. Here we report the preparation and comprehensive properties of a new family of universal HPGs (U-HPGs) that can be mass-produced with moderate conditions by sintering NFG slightly mixed with diamond, where units of onion carbon (OC) with NFG (OC@NFG) act as building blocks. OC@NFG creates a strong interfacial network between the NFGs, giving the U-HPGs outstanding strength and moderate hardness. With U-HPGs being more than 93 % graphitization, the flexural strength exceeds 100 MPa, far superior to mainstream commercial graphites. OC@NFG also bestows U-HPGs with excellent thermal conductivity(＞125 W m−1 K−1 at room temperature). For such structure provides a 3D path for electrons inside U-HPGs, the as-produced material has significant electronical conductivity. This work presents new insights into this old yet important material and allows for innovative design of HPGs for various applications.

Oriented Three-Dimensional Skeletons Assembled by Si3N4 Nanowires/AlN Particles as Fillers for Improving Thermal Conductivity of Epoxy Composites.

With the miniaturization of current electronic products, ceramic/polymer composites with excellent thermal conductivity have become of increasing interest. Traditionally, higher filler fractions are required to obtain a high thermal conductivity, but this leads to a decrease in the mechanical properties of the composites and increases the cost. In this study, silicon nitride nanowires (Si3N4NWs) with high aspect ratios were successfully prepared by a modified carbothermal reduction method, which was further combined with AlN particles to prepare the epoxy-based composites. The results showed that the Si3N4NWs were beneficial for constructing a continuous thermal conductive pathway as a connecting bridge. On this basis, an aligned three-dimensional skeleton was constructed by the ice template method, which further favored improving the thermal conductivity of the composites. When the mass fraction of Si3N4NWs added was 1.5 wt% and the mass fraction of AlN was 65 wt%, the composites prepared by ice templates reached a thermal conductivity of 1.64 W·m-1·K-1, which was ~ 720% of the thermal conductivity of the pure EP (0.2 W·m-1·K-1). The enhancement effect of Si3N4NWs and directional filler skeletons on the composite thermal conductivity were further demonstrated through the actual heat transfer process and finite element simulations. Furthermore, the thermal stability and mechanical properties of the composites were also improved by the introduction of Si3N4NWs, suggesting that prepared composites exhibit broad prospects in the field of thermal management.

Deformation characteristics of dense and foamed mortars based on cement and gypsum-to-cement binders for 3D printing

Construction 3D printing is one of the revolutionary construction technologies, which involves the use of highly fluid cement and gypsum-to-cement mixes. However, this requires an additional study of the deformation characteristics of multicomponent materials. The article is devoted to the study of the own deformation characteristics of mortars based on cement and gypsum-to-cement binders, as well as fine-grained concrete for printing the contours of wall structures and foamed mortar for filling, monolithic and thermal insulation of their internal space. A wide range of cement and gypsum-to-cement materials has been studied, incl. foamed mortar. For these materials, comprehensive studies of deformation characteristics have been carried out, confirming the results obtained by X-ray diffraction analysis, SEM, heat of hydration, fresh and physical and mechanical properties. It has been established that in gypsum-to-cement materials, the revealed deformations of the expansion of gypsum overlap the negative deformations of air shrinkage. The resulting materials have a slump flow up to 226 cm, which allows the use of these materials for 3D printing of building structures. The high strength of the developed cement and gypsum-to-cement materials in all periods of hardening (above 50 MPa), as well as excellent thermal conductivity (0.10–0.13 W/(m·°C)), shows the promise of fine-grained mortars and foamed ones.

Zwitterionic carbon quantum dots incorporated ultrafiltration membrane for efficient removal of copper ion

Copper, prized for its excellent thermal and electrical conductivity, poses risks when present in wastewater. Treating copper ion-containing wastewater is vital for human and environmental safety. Membrane separation technology offers an eco-friendly and energy-efficient solution. In this study, a mixture of cellulose acetate (CA) and thermoplastic polyurethane (TPU) was used to fabricate the tubular membrane, with quantum dots (QDs) added. Three types of QDs were introduced into the tubular membrane: carbon quantum dots (CQDs), tertiary amine CQDs (TQDs), and zwitterionic CQDs (ZQDs). At pH = 10, copper ions were chelated with sodium dimethyldithiocarbamate (SDDC) at a ratio of SDDC/Cu2+=10 (w/w), signifying a molar concentration (mol.L-1) ratio of SDDC:Cu2+=3:16. This process achieved a 99.8% removal rate of copper ion. The ZQDs-M exhibited high pure water flux of 6,227.4 L.m−2.h−1.bar−1 and 95.4% copper ion-complex rejection rate. The ZQDs-M also demonstrated excellent anti-adhesion properties, with only 4.55% relative fluorescence intensity of E. coli and 34.58% BSA adsorption. The BSA dynamic anti-fouling property of the ZQDs-M was also superior to that of tubular membrane without QDs addition.

Machine learning approach for predicting compressive strength in foam concrete under varying mix designs and curing periods

Efforts to reduce the weight of buildings and structures, counteract the seismic threat to human life, and cut down on construction expenses are widespread. A strategy employed to address these challenges involves the adoption of foam concrete. Unlike traditional concrete, foam concrete maintains the standard concrete composition but excludes coarse aggregates, substituting them with a foam agent. This alteration serves a dual purpose: diminishing the concrete’s overall weight, thereby achieving a lower density than regular concrete, and creating voids within the material due to the foam agent, resulting in excellent thermal conductivity. This article delves into the presentation of statistical models utilizing three different methods—linear (LR), non-linear (NLR), and artificial neural network (ANN)—to predict the compressive strength of foam concrete. These models are formulated based on a dataset of 97 sets of experimental data sourced from prior research endeavors. A comparative evaluation of the outcomes is subsequently conducted, leveraging statistical benchmarks like the coefficient of determination (R2), root mean square error (RMSE), and mean absolute error (MAE), with the aim of identifying the most proficient model. The results underscore the remarkable effectiveness of the ANN model. This is evident in the ANN model’s R2 value, which surpasses that of the LR model by 36% and the non-linear model by 22%. Furthermore, the ANN model demonstrates significantly lower MAE and RMSE values compared to both the LR and NLR models.

Temperature and photo sensitive PVDF-g-PNIPAAm/BN@PDA-Ag nanocomposite membranes with superior wasterwater separation and light-cleaning capabilities

Traditional water treatment membranes always face the problem of membrane contamination in the practical application. Those contaminants deposited on the membrane surface and inside the membrane pores make the filtration process more difficult. Herein, the temperature and photo sensitive nanocomposite membranes with superior wasterwater separation and light-cleaning capabilities were prepared by a non-solvent induced phase separation method, which combined the thermo-responsive property of poly(N-isopropylacrylamide) (PNIPAAm) grafted polyvinylidene fluoride (PVDF) and the high photothermal conversion character of core–shell structured BN@PDA-Ag nanosheets. The membranes can be heated to high temperature within a short period of light exposure due to the fast photothermal conversion capability of Ag and the excellent thermal conductivity of boron nitride (BN). The increase in temperature led to the contraction of PNIPAAm chains and bigger pore size. The microstructure, filtration, and cleaning performance of the nanocomposite membranes can be controlled by illumination, which allowed PVDF-g-PNIPAAm/BN@PDA-Ag membranes to achieve the effect of first interception and then cleaning. The membranes showed retention rates of 82, 99 and 95 % for BSA, oil–water emulsions and various dyes with flux recovery rates of > 90 % after light cleaning. This work provides a simpler, more efficient membrane cleaning strategy with superior potential for dealing with membrane contamination.

Principle & application of energy storage based on 2D material: Evidence from graphene

The development of new energy and related industries has raised higher requirements for energy storage devices. Graphene, a 2-D carbon material with a single atomic layer thickness, possesses excellent mechanical properties, thermal conductivity, SSA, optical transparency, and rapid electron migration, among other unique physical and chemical properties. The addition of graphene is predicted to enhance the rate performance, durability and energy density of electrochemical energy storage devices. This study summarizes the recent research in the production and application of graphene in electrochemical energy storage devices, primarily focusing on supercapacitors and the positive and negative electrode of lithium-ion batteries. The main roles of graphene include serving as an ultrathin support and buffering material, an active substance, and a conductive material. In addition, the limitations of graphene due to its production technologies and the potential brought by its super flexibility and lightweight properties are discussed. Finally, a brief outlook in the field of graphene is provided.

Polycrystalline diamond obtained in the diamond-Mo system with enhanced thermal stability sintered by HPHT

This study provides thermoanalytical data on polycrystalline diamond (PCD) sintered in the diamond-Mo system at high pressure-high temperatures (HPHT). PCD is a key material for the abrasive tool industry, given its unprecedented hardness and wear resistance, as well as its excellent thermal conductivity. These characteristics make it highly effective in drilling into rock formations and machining non-ferrous materials, such as titanium alloys. A critical issue in the performance and lifetime of polycrystalline diamond, however, is its low thermal stability, which limits its potential applications. Accordingly, PCD with enhanced thermostability was obtained in the diamond-Mo system, with resistance graphitization and oxidation around 200 °C higher than conventional PCD. The superior thermal performance seen for PCD-Mo may be due to the formation of in situ carbides (MoC and Mo2C), which inhibit the evolution of graphitization and oxidative processes.

Investigation of 1-tetradecanol with functionalized multi-walled carbon nanotubes as PCM for high-density thermal energy storage

To evaluate a potential thermal battery material for thermal energy storage applications, this study prepared a stable organic nano-dispersed PCM (NDPCM) with 1-tetradecanol (TD) with a melting point and latent heat of 37.8 °C and 236.4 J/g, respectively, as base PCM and investigated its thermal properties. The high thermal conductive nano-additives of functionalized multi-walled carbon nanotubes (MWCNT-COOH) with a concentration range of 1 wt% to 5 wt% were infused in the pure PCM. As a result, MWCNT-COOH shows better dispersion stability. The SEM microimage confirms no agglomeration was observed for the prepared NDPCM. The supercooling was reduced from 10.6 °C for the pure TD to 7.7 °C for TD with 5 wt% of MWCNT. The latent heat of the NDPCM with 5 wt% MWCNT-COOH was 212.6 J/g with a 10% reduction compared to pure TD. The reduction in latent heat values is lower than the previously investigated TD composite PCM. The thermal stability study through gravimetric analysis confirms that the decomposition of the NDPCMs initiates at 200 °C, which will not be affected by thermal fluctuation in the system. The sample with 5 wt% of nano-additives had the most excellent thermal conductivity (TC) improvement, 56.2% in the liquid phase, whereas 50% in the solid phase. The reported values are significantly higher compared to the previous thermal conductivity improvement of TD using metallic nanoparticles. The prepared NDPCM shows better thermal properties than the pure PCM and can be a possible material for high-density thermal energy storage applications.

Formation of aluminum nitride nanofibers using electrospinning and their application to thermal conductive sheets

Aluminum nitride (AlN) nanofibers were formed by heating polyvinyl alcohol (PVA)/boehmite precursor nanofibers at various temperatures in nitrogen gas flow. We designed AlN nanofiber as an effective thermal conductive filler to create long linear heat-transfer pathways in the resin. Aligned AlN nanofiber mats were fabricated using electrospinning of PVA/boehmite composite aqueous solution and were impregnated with polyvinyl butyral (PVB) solutions. The obtained sheets containing the aligned AlN nanofiber 47, 52, and 54 vol% had excellent thermal conductivity, 22, 21, and 19 W/(m·K), for aligned nanofibers direction in the sheet. The PVB/AlN nanofibers composite sheet also showed good electrical insulating properties below 1.0 × 1012 Ω/cm2.Graphical

Effect of heat treatment on mechanical properties of CuCrZr triply periodic minimal surface structures fabricated by selective laser melting

CuCrZr alloy has excellent conductivity, thermal conductivity, friction reduction and abrasion resistance, which can satisfy in different fields. Copper alloy porous structure is a new multifunctional structure with both structural and functional properties. Selective laser melting (SLM) technology has certain advantages for the preparation of periodic porous structures with triply periodic minimal surfaces (TPMS). Under the background of SLM technique, the quasi-static compression properties of Diamond and Gyroid porous structures were studied. The whole deformation of structures was captured by digital camera, and the failure mechanism was analyzed by finite element software. The effects of different heat treatments on the microstructure and mechanical properties of the CuCrZr were studied by scanning electron microscopy and compression tests. The microstructure morphologies show that the number of curved grains decreases and the grains become more regular after heat treatment. Heat treatment can optimize the mechanical properties and energy absorption capacity of the material, which is most obvious at 500 °C. These results indicate that specific heat treatment can improve the stability and predictability of the CuCrZr porous structure.

Process development for laser powder bed fusion of GRCop-42 using a 515 nm laser source

Copper is widely used in high heat flux and electrical applications because of its excellent electrical and thermal conductivity properties. Alloying elements such as chromium or nickel are added to strengthen the material, especially for higher temperatures. Cu4Cr2Nb, also known as GRCop-42, is a dispersion-strengthened copper-chromium-niobium alloy developed by NASA for high-temperature applications with high thermal and mechanical stresses such as rocket engines. Additive manufacturing (AM) enables applications with complex functionalized geometries and is particularly promising in the aerospace industry. In this contribution, a parametric study was performed for GRCop-42 and the AM process laser powder bed fusion (PBF-LB/M) using a green laser source for two-layer thicknesses of 30 and 60 μm. Density, electrical conductivity, hardness, microstructure, and static mechanical properties were analyzed. Various heat treatments ranging from 400 to 1000 °C and 30 min to 4 h were tested to increase the electrical conductivity and hardness. For both layer thicknesses, dense parameter sets could be obtained with resulting relative densities above 99.8%. Hardness and electrical conductivity could be tailored in the range of 103–219 HV2 and 24%–88% International Annealed Copper Standard (IACS) depending on the heat treatment. The highest ultimate tensile strength (UTS) obtained was 493 MPa. An aging temperature of 700 °C for 30 min showed the best combination of room temperature properties such as electrical conductivity of 83.76%IACS, UTS of 481 MPa, elongation at break (A) at 24%, and hardness of 125 HV2.

Effect of pulsation parameters on the spatial and temporal variation of flow and heat transfer characteristics in liquid metal cross flow the in-line tube bundle

Liquid metal has a broad application prospect in tube bundle heat exchangers because of its excellent thermal conductivity. However, conventional in-line tube bundle arrangements often exhibit limited secondary flow, so new methods are urgently needed to improve heat transfer. The topic of this paper is to combine two methods, liquid metal cross flow tube bundle and pulsating flow, to improve the heat transfer performance in-line tube bundles. Firstly, the applicability of the model was validated through experimental data from existing literature, encompassing overall flow dynamics, heat transfer performance, and circumferential pressure distribution around the tubes. Subsequently, numerical simulations are conducted involving liquid metal cross flow in-line tube bundles at varying pulsating frequencies, amplitudes, and Reynolds numbers. Circumferential pressure distributions and temperature profiles for individual tubes were analyzed and compared. The amplitude of reduction in thermal resistance compared to the no-oscillation condition increases gradually from a minimum of 8 % in the first row to a maximum of 40 % in the third row, while the reduction in the rear row of tubes is similar to that of the third row. Remarkably, a reversal in the trend of thermal resistance for the first three rows of tubes under pulsating flow were observed, contrasting conventional flow except for the case with an amplitude of 0.1. By analyzing the local transient flow field distribution near single tube and the corresponding circumferential heat transfer performance, the influence of the vortex evolution characteristics on the heat transfer performance at different phases of the pulsating velocity is revealed, which transient Nu is up to three times that of flow with no pulsating. Finally, a series of coherence analyses reveal that as frequency rises, turbulence exhibits a richer spectrum of small-scale vortex structures, intricately linked to enhanced energy cascade efficiency. Amplitude augmentation intensifies velocity fluctuations, particularly at high amplitudes, resulting in substantial energy peak amplification. The integrated heat transfer performance PEC factor varies in the range of 1.25 to 1.51 for all the conditions simulated in this paper, which indicates that the liquid metal coupled pulsating flow approach can significantly increase the comprehensive performance of the tube bundle heat exchangers. These findings hold significant promise for advancing heat exchanger design and enhancing thermal efficiency, with implications for various engineering applications.

Immobilization of nanodiamonds onto cotton fabric through polyurethane nanofibrous coatings for summer clothing

AbstractGlobal warming is one of the alarming issues, which is impacting humans globally. It is preferred to adopt a lifestyle that promotes heat dissipation from the human body. One approach to cool a human body is improvement in personal apparel, which can help the human body to cool quickly. The required characteristic for cooling performance can be achieved by employing materials with excellent thermal conductivity. Nanodiamonds (ND) have exceptional thermal conductivity properties and can help overcome the poor thermal conductivity of fabrics. This manuscript presents a study on a one‐sided coated fabric where NDs are applied to the skin side of the fabric to promote heat dissipation toward the atmosphere while the other side of the fabric, exposed to the hot atmosphere, remains uncoated to delay the transfer of out from atmosphere to human body. ND was applied onto cotton fabric through electrospraying polyurethane (PU) and carboxylated ND (NDCOOH). Scanning electron microscope (SEM) and optical microscopy images indicated a homogeneous distribution of the sprayed ND/PU solution over the fabric surface. The samples were chemically analyzed by Fourier transform infrared spectroscopy (FTIR). The thermal resistance was measured by a sweating guarded hot plate (SGHP), which confirmed lower thermal resistance of fabric from the ND‐coated side to atmosphere as compared to control, and thermal resistance from the uncoated to atmosphere was the same for both controlled and treated samples. Similarly, thermal conductivity, radiant heat transfer, and infrared spectroscopy characterizations strengthened the findings of SGHP results. Real‐life simulated experiments were also conducted to verify the performance of developed samples. The electrosprayed samples also showed higher ultraviolet protection than the control sample. Air permeability and moisture absorption of the samples slightly decreased after applying the coating but remained within an acceptable range of comfortability. The developed fabric can promote energy conservation, as it will warm slowly but cool quickly. This allows home or office temperature setpoints for localized cooling to be 2–3°C lower with a projected energy savings between 20% and 30%.

Structural and electronic phase transitions of thorium monoxide from first-principles calculations

Because of the innovative concepts for creating the thorium fuel cycle as an alternative nuclear energy source, thorium and its compounds have attracted a lot of attention. It is essential to study the physical properties that are necessary for the basic understanding and practical application of these materials. Thorium monoxide has already drawn researchers' attention as a metal oxide. Under different pressure conditions, the crystal structures, electronic band structures, phonon dispersions, mechanical properties, and thermodynamic properties of ThO have been determined using a particle swarm optimization structure prediction method in conjunction with first-principles calculations. Previous experiments agree with our results for the lattice constants of the phase of Fm3‾m. Moreover, a novel structure of R-3m is predicted to be thermally stable at a pressure of roughly 22 GPa. The phase is then also mechanically and dynamically stable, according to the findings of our computed elastic constants and phonon dispersion. The phase change from Fm3‾m to R-3m has not, however, been associated with any electronic transitions, and as both phases are mental, they may have excellent thermal conductivity. We further calculated the results of the Helmholtz free energy, entropy, specific heat, internal energy, bulk modulus, shear modulus, Young's modulus, Poisson's ratio, and Debye temperature based on the stable dynamics and mechanical properties, which reveal that they all could be good fuel. The results provide key insights into understanding the structural and electronic behaviors of ThO under the condition of external pressure.

PERFORMANCE EVALUATION OF PALM OIL CLINKER AS CEMENT AND SAND REPLACEMENT MATERIALS IN FOAMED CONCRETE

Cellular lightweight concrete (CLC), also known as foamed concrete, has been extensively used in construction for decades. Foamed concrete’s properties include low density, excellent thermal conductivity, great workability, and selfcompaction; these features enable foamed concrete to be utilized in various contexts. However, the excessive use of conventional materials in concrete production harms the environment. Therefore, using agro-waste as a material to construct ecologically sustainable structures has numerous practical and financial benefits. Palm oil clinker (POC) is a waste product resulting from solid waste combustion during palm oil extraction. This research focused on the properties of foamed concrete with POC at 0%, 25%, 50%, 75%, and 100% as the fine aggregate replacement to develop lightweight foamed concrete (LFC) with a density of 1300 kg/m3. Besides, the potential of POC powder (POCP) and thermally activated POCP (TPOCP) at 0%, 10%, 20%, and 30% as cement replacements was examined. The development of compressive strength during a 90-day curing period was investigated. In addition, tensile and flexural strengths were assessed and reported, and the elastic modulus of the LFC was discussed. The transport properties of water absorption, porosity, and sorptivity were also investigated. The durability of concrete derivatives can exhibit the product’s resistance to chemical attacks and environmental conditions. After 75 days of immersion in hydrochloric acid and magnesium sulfate, the chemical resistivity of the produced LFC was determined by measuring the loss in weight and compressive strength. In addition, the effects of elevated temperatures on the LFC were determined by analyzing the mass loss and compressive strength degradation of specimens exposed to temperatures ranging from 200 to 800 °C. The test results demonstrated that the complete replacement of sand with POC enhanced the compressive strength of LFC by more than 50%. Similarly, POC-based LFC had higher flexural and tensile strengths than normal LFC. Besides, substituting 20% of cement with TPOCP could improve the strength of LFC by 23% during the initial curing days. Utilizing the optimal proportions of POC and POCP could enhance the residual strengths of LFC. Therefore, POC has the potential to be utilized as a fine aggregate and cementitious material to produce sustainable concrete.

Nanographite/nanosilica-filled dopamine-containing polyacrylamide hydrogels of temperature-sensitive photothermal responses

Conductive hydrogels are of significant interest because of their important applications in flexible electronics, energy storage, and human-computer interaction. However, the deficiencies of weak electrical conductivity and mechanical properties seriously hinder the applications of conductive hydrogels in these frontier areas. In this research, conductive hydrogels with high electrical conductivity, excellent self-recovery properties and outstanding photothermal effects are prepared by synergistic interaction of dopamine, silica nanoparticles, graphite nano-powder (Grn) and polyacrylamide chains. The effects of Grn and temperature on the conductivity of the hydrogels are investigated in detail. The hydrogels feature highest conductivity (7.2 mS/cm) and even 9.1 mS/cm at 60 °C due to the excellent thermal and electrical conductivity of Grn, which also endows the hydrogels with excellent photothermal effect and stable energy storage properties. Notably, the catechol group of dopamine (DA) leads to excellent self-adhesive properties of the conductive hydrogels. The use of silicon dioxide nanoparticles (SNs) allows the conductive hydrogels to obtain favorable toughness as well as self-recovery properties. This provides a broad prospect for the applications of conductive hydrogels in practice.

Environmental-friendly biomass-based Janus ink/urushiol modified cotton fabric for efficient solar-driven interfacial evaporation

Much attention has been paid to the interfacial solar-thermal conversion method for water resource purification. According to the hydrophilicity of ink carbon particles and the amphiphilicity of urushiol molecules (the main compound of Chinese lacquer), a novel environmentally friendly biomass Janus ink/urushiol modified cotton fabric was successfully prepared and exhibited one hydrophilic side and one hydrophobic side through simple immersion and spraying treatments. The Janus fabric displayed excellent water transport behavior, mechanical stability, thermal conductivity, and photothermal conversion performance. Under one stimulated solar radiation, the temperature of the Janus fabric increased to 85 °C in 2 min. Additionally, a photothermal vapor device prepared using a polyethylene ring and the Janus fabric demonstrated a high conversion efficiency of 94.3% with an impressive evaporation rate of 1.64 kg m−2h−1, which was 3.35 times the rate of water evaporation in the absence of the modified fabric. The Janus fabric showed satisfactory resistance to ultraviolet radiation and pH values. After 8 cycles (every 10 h) of exposure to outdoor sunlight, the modified fabric showed a slightly decreased evaporation rate, which could be restored to the previous level by re-spraying ink on the modified fabric. In the concentrated salt solutions, the solar-driven evaporator displayed excellent salt rejection capacity. During the desalination of high-concentration saline water, the Janus fabric showed acceptable diurnal correspondence. After desalination, the water quality reached the required standards for drinking water. In particular, the B3+ content droppingto 0.33 mg L−1(below the thresholdof 0.5 mg L−1). The solar steam generator also showed remarkable purifying capabilities for wastewater containing heavy metals and organic dyes. The Janus ink/urushiol fabric, prepared in an easy way, has a wide range of applications in seawater desalination and sewage treatment, which can be applied for mitigation of freshwater crises and environmental remediation.