Foam-like Structure Research Articles

A comparative study of wet-mix vs. dry-mix to prepare geopolymer artificial aggregates utilizing municipal solid waste incineration bottom ash (IBA) via crushing technique

The demand for sustainable alternatives to utilize incinerator bottom ash (IBA) alongside the current scarcity of natural aggregates drives the construction industry to seek innovative solutions, among which cold bonding geopolymer artificial aggregates (GPA) have tremendous leverage. This study suggests combining dry-mix and crushing techniques for producing IBA-GPA, aiming to overcome the challenges of volume instability related to metallic aluminum. The materials used as precursors include IBA, CFA, and GGBS, with anhydrous sodium metasilicate as the activator. The mixing method, water content, and IBA content are key parameters examined in this research, using characterization techniques such as XCT, TCLP, XRD, FTIR, and SEM. The results show that a proper balance between water and IBA contents is crucial for producing high-quality IBA-GPA cubes, at which the proposed technologies successfully mitigate volume instability and enhance the reliability of IBA-GPA. The dry-mix samples were less porous and more compact, with irregularly shaped pores, while the wet-mix samples had a foam-like structure with more uniformly spherical pores. Adding IBA increased pore sizes in both samples, with a more pronounced effect in the wet-mix samples. The findings provide insights into the impact of mixing methods on the properties of IBA-GPA.

Chondroitin Sulfate and Hyaluronic Acid-Based PolyHIPE Scaffolds for Improved Osteogenesis and Chondrogenesis In Vitro.

Osteochondral damage, affecting the articular cartilage and the underlying subchondral bone, presents significant challenges in clinical treatment. Such defects, commonly seen in knee and ankle joints, vary from small localized lesions to larger defects. Current medical therapies encounter several challenges, such as donor shortages, drug side effects, high costs, and rejection problems, often resulting in only temporary relief. Highly porous emulsion-templated polymers (polyHIPEs) offer numerous potential benefits in the fabrication of scaffolds for tissue engineering and regenerative medicine. Polymeric scaffolds synthesized using a high internal phase emulsion (HIPE) technique, called PolyHIPEs, involve polymerizing a continuous phase surrounding a dispersed internal phase to form a solid, foam-like structure. A dense, porous design encourages cell ingrowth, nutrient delivery, and waste disposal from the scaffold, mimicking the cells' natural microenvironment. This study used hydroxyethyl methacrylate (HEMA) and acrylamide (AAM) polyHIPE scaffolds combined with extracellular matrix (ECM) components of the tissue, such as methacrylated hyaluronic acid (MHA) and methacrylated chondroitin sulfate (MCS), to prepare polyHIPE scaffolds. The mouse preosteoblast MC3T3-E1 cells and primary rat chondrocytes (harvested from male Wistar rats) were seeded on the scaffolds and cultured for 21 days to assess the osteogenesis and chondrogenesis in vitro. When compared to the AAM-MHA and AAM-MCS groups at day 21, scaffold groups HEMA-MHA and HEMA-MCS showed a significant rise in alkaline phosphatase (ALP) and calcium content. Chondrogenic markers such as glycosaminoglycan (GAG) and hydroxyproline were also assessed over a 21-day time point. On day 21, it was found that GAG and hydroxyproline production were considerably higher in the HEMA-MHA and HEMA-MCS scaffolds than in the AAM-MHA and AAM-MCS scaffolds. The overall studies showed that polyHIPE monolith scaffolds could favor cell adherence, survival ability, proliferation, differentiation, and ECM formation over 21 days. Thus, incorporating ECM components enhanced osteogenesis and chondrogenesis in vitro and can be further used as tissue repair models.

Origin of Fracture-Controlled Conduits in Calcite-Rich Highly Productive Aquifers Impregnated with Diagenetic Silica

The origin of highly permeable flow paths in carbonate-siliciclastic rocks, such as large-aperture fractures in aquifers in the Eastern Bohemian Cretaceous Basin (EBCB), is poorly understood. The karst potential was assessed from the rock carbonate content and the degree of disintegration after leaching in HCl. Surprisingly, dissolution of calcite in EBCB usually did not lead to rock disintegration until calcite > 78%. Instead, porosity increased significantly. High-porosity rock is held together by microns-thick secondary silica cement with a foam-like structure and considerable tensile strength. Three types of conduits occur in the EBCB: (i) bedding-parallel conduits associated with calcite-rich layers, (ii) subvertical fracture swarm conduits that develop on damaged zones of fracture swarms, and (iii) conduits formed by dissolution of calcite veins by groundwater flow. These are ghost-rock karst features where calcite is leached from the rock in the first phase and the residue is washed out by conduits under steep hydraulic gradients in the second phase. Very similar features have been described in Minnesota and Wisconsin, USA. Research has shown that fractures with sharp-edged walls that give the impression of an extensional tectonics origin may actually be ghost-rock karst features in which dissolution and piping have played an important role in their enlargement.

Natural Fiber Reinforced Shoe Midsoles with Balanced Stiffness/Damping Behavior.

The comfort of walking depends heavily on the shoes used. Consequently, the midsole of shoes is designed in such a way that it can dampen force peaks during walking. This significantly increases the overall wellness during walking. Therefore, the midsole usually consists of rubber-like polymers, such as polyurethane and ethylene-vinyl acetate copolymer. Furthermore, the manufacturing process of these polymers results in a foam-like structure. This further enhances the damping behavior of the material. Nevertheless, it would be desirable to find a cheap and sustainable method to enhance the damping behavior of the shoe midsole. The purpose of this work is to see if hemp fibers, which are part of the polymer matrix material, could improve the stiffness without losing the damping behavior. The mechanical properties of such prepared fiber-reinforced composites were characterized by quasi-static tensile testing and dynamic mechanical analysis. The mechanical properties were examined in relation to the fiber type, weight fraction, and type of polyurethane used. Furthermore, the investigation of the embedding of these fibers in the polymer matrix was conducted through the utilization of optical and electron microscopy.

Synergistic advancements in high-performance flexible capacitive pressure sensors: structural modifications, AI integration, and diverse applications.

The development of flexible pressure sensors for monitoring human motion and physiological signals has attracted extensive scientific research. However, achieving low monitoring limits, a wide detection range, large bending stresses, and excellent mechanical stability simultaneously remains a serious challenge. With the aim of developing a high-performance capacitive pressure sensor (CPS), this paper introduces the successful preparation of a single-walled carbon nanotube (SWNT)/polydimethylsiloxane (S-PDMS) composite dielectric with a foam-like structure (high permittivity and low elasticity modulus) and MXene/SWNT (S-MXene) composite film electrodes with a micro-crumpled structure. The above structurally modified CPS (SMCPS) demonstrated an excellent response output during pressure loading, achieving a wide pressure detection range (up to 700 kPa), a low detection limit (16.55 Pa), fast response/recovery characteristics (48/60 ms), enhanced sensitivity across a wide pressure range, long-term stability under repeated heavy loading and unloading (40 kPa, >2000 cycles), and reliable performance under various temperature and humidity conditions. The SMCPS demonstrated a precise and stable capacitive response in monitoring subtle physiological signals and detecting motion, owing to its unique electrode structure. The flexible device was integrated with an Internet of Things module to create a smart glove system that enables real-time tracking of dynamic gestures. This system demonstrates exceptional performance in gesture recognition and prediction with artificial intelligence analysis, highlighting the potential of the SMCPS in human-machine interface applications.

Transition from a foam-like to an onion-like nanostructure in water-rich L3 phases

Abstract In dilute water-surfactant systems L3 phases are found in which bilayers interconnect to form a sample-spanning sponge-like structure. From our previous study of the system water/NaCl-AOT (sodium bis(2-ethylhexyl) sulfosuccinate) we know that a transition of this sponge-like structure to an oil-continuous foam-like structure occurs upon addition of minute amounts of oil (about 3 wt%, α = 0.03) in the L3 channel at a constant surfactant mass fraction of γ = 0.15 and T = 25 °C. The aim of the present study was to verify if the same transition occurs at γ = 0.25. To achieve this goal, we determined the relevant part of the phase diagram and studied the electrical conductivities and viscosities within the narrow one-phase L3 channel. Although the electrical conductivities and viscosities change qualitatively like those observed at γ = 0.15 we did not observe a sponge-like structure at γ = 0.25 in the oil-free system (α = 0) with freeze-fracture electron microscopy (FFEM) and freeze fracture direct imaging (FFDI). Together with the FFEM/FFDI images and SANS/SAXS curves we provide experimental evidence for a structural transition with decreasing oil content from a thermodynamically stable foam-like to a thermodynamically stable onion-like nanostructure at γ = 0.25 rather than to a sponge-like structure as is the case at γ = 0.15.

Graphene induced carbon-based fibre composite as microwave absorber for X-band frequency application

Stealth performance for any microwave absorbing material (MAM) is primarily controlled by the intrinsic characteristic properties of the composition of the composite. The inbuilt property of graphene has enrich the interaction of electromagnetic waves (EMWs) when it is impregnated in its compatible components such as naturally occurring organic materials. The present research engraved with a natural fibre composite with graphene as a stuffing in a resin polymer environment. The powdered form of banana-coconut coir fibre dust with 50–50 wt.% of average particle size of 150 µm with graphene has been fabricated as a hybrid composite of Graphene/Banana-coconut (GN/BNN-CCNT). The surface morphology of the fabricated composite is significantly modified with the addition of graphene creating a sustainable and foam-like elastic skeletal structure for compatibility with EMW. The enhanced dielectric values with different microwave properties for stealth performance are computed. At a frequency of 10.63 GHz a significant −15.68 dB reflection loss is found which comprises of power loss of 97.5% showing the effectiveness of the GN/BNN-CCNT/Epoxy hybrid composite as a stealth material for different X band frequency applications.

Using xenon K-edge subtraction to image the gas-accessible porosity distribution within metallurgical cokes and their partially reacted products

The performance and reactivity of coke in a blast furnace is critically dependent on the accessibility of the coke structure to carbon dioxide (CO2) gas. We used xenon gas K-edge subtraction in synchrotron micro-CT imaging to probe the extent to which gas could penetrate the microstructure of six different metallurgical cokes made from Australian coals. We compared the distribution of the xenon sorbed by the coke samples before and after reaction with CO2 at 1100 °C to 20–30% mass loss. Xenon is as strongly sorbed onto surfaces as carbon dioxide and can thus be used as an x-ray-visible analogue of CO2. Aside from traces of pyrolysis ash, coke comprises two major components; the reactive maceral derived component (RMDC), which passes through a molten state during coke manufacture to form a foam-like structure, and the inertinite maceral derived component (IMDC), which are particles ranging from a few microns to a few millimetres in size, embedded in the RMDC. These components were found to behave very differently in this study. Prior to reaction, the RMDC component sorbed only a small amount of xenon and most of the IMDC sorbed little to no xenon. However, a small fraction of the IMDC took up significant quantities of xenon in high concentration. This suggests that a significant fraction of the surface area of unreacted coke comes from rare, high-surface-area IMDC components.Imaging of the coke after reaction showed the RMDC still sorbed only small amounts of xenon, indicating that the surface area in these components was largely unchanged. However, the previously xenon-inaccessible IMDC regions sorbed large quantities of xenon after reaction, reaching peak xenon densities many times that seen in the free xenon gas. Thus, surface area is produced by reaction with CO2 or (more probably) much of the pre-existing surface area is made accessible by reaction. This shows that IMDC provide most of the reacting surface during early stages of reaction of coke with CO2. This was confirmed by the corresponding loss of mass seen in these IMDC particles relative to the RMDC.

Solvent-free synthesis of Co/CoNx encapsulated by N-doped, sucrose-derived porous carbon as bifunctional air cathode catalyst for high-energy rechargeable zinc-air batteries

Rechargeable zinc-air batteries have a substantial theoretical energy density while potentially being manufactured at a minimized cost. Hence, developing low-cost bifunctional electrocatalysts is of crucial importance. Herein, the synthesis of an electrocatalyst containing zinc/cobalt species encapsulated in a nitrogen-doped carbon matrix modulated with a large number of carbon nanotubes (ZnCo@CN) was developed through a facile thermal method under solvent-free conditions. Using bio-based sucrose in the presence of inorganic catalysts (Zn/Co) resulted in a Zn/Co carbon foam-like structure. Subsequently, the high-temperature treatment with the addition of 2-methylimidazole resulted in a unique material (ZnCo@CN). The incorporation of highly active species dispersed in hierarchical porous carbon presented an excellent bifunctional electrocatalyst for ORR (half-wave potential of 0.85 V) and OER (overpotential of 327 mV). The assembled zinc-air battery with ZnCo@CN as a bifunctional air cathode exhibited an excellent power density of 206 mW cm-2 and an astonishing energy density of 983 Wh Kg-1.

Enhancing zein-starch dough and bread properties by addition of hydrocolloids

Similar to gluten, zein can form a viscoelastic network upon hydration and shear. This makes zein a promising protein to develop gluten-free bakery products. In this study, the effect of addition of different hydrocolloids (hydroxypropyl methylcellulose (HPMC), guar and xanthan gum), and the inclusion of pregelatinized starch (PG starch) and lactic acid (LA) on zein-corn starch dough and bread properties was examined. The addition of HPMC, and to a lesser extent guar gum, significantly changed the viscoelastic zein dough properties and resulted in bread samples with improved loaf volume and sensory properties. Scanning electron microscopy revealed the formation of a continuous fine foam-like structure in the zein-starch dough when HPMC and guar gum were added. This finer structure translated in a lower dough stiffness and resistance to deformation, and a higher degree of deformation characterized by lower complex moduli and increased creep compliance values. Xanthan gum addition, conversely, had an adverse effect on zein bread loaf volume which was attributed to potential weak repulsion between xanthan and zein molecules. In addition, the amount of α-helix and β-sheet secondary structures in bread samples was altered upon hydrocolloid and PG starch addition and played a role in bread crumb hardness. Overall, the zein bread with HPMC showed textural properties most similar to gluten bread. This research sheds light on different structure levels of zein-based gluten-free recipes as affected by inclusion of hydrocolloids, PG starch and LA, and provides a sound basis for the rational development of zein-based gluten-free breads.

Effect of Sintering Temperature on the Structural and Morphological Properties of Hydroxyapatite Prepared by Precipitation Method

Hydroxyapatite nanoparticles (HAp-NPs) were prepared using a precipitation route from an aqueous solution at a 1.66 Ca/P ion ratio and sintered at different temperatures. X-ray diffraction (XRD) was used to investigate the structural properties of the prepared films. Using a Field Emission Scanning Electron Microscope, the morphology of the surfaces was analyzed. Using Fourier Transform Infrared (FTIR) Spectroscopy, the surface's chemical composition and chemical bonding information were identified. The structural analysis shows that heating treatment reduced the broadening of diffraction peaks, enhancing the Hydroxyapatite phase crystallinity. No phase transition was observed as the sintering temperature increased, revealing the HAp phase's high stability. SEM micrograph images revealed a nanostructured foam-like structure that changed into a flake-shaped structure with diameters between 300 nm and 600 nm after heat treatment. FTIR spectroscopy results revealed that the heat treatment improved the crystallization of the developed HAp-NPs samples. Barrett-Joyner-Halenda (BJH) was used to determine the pore size of HAp NPs, whereas Brunauer-Emmett-Teller (BET) analysis was employed to characterize the surface area of the samples.

Capacitive Sensors with Hybrid Dielectric Structures and High Sensitivity over a Wide Pressure Range for Monitoring Biosignals

Various dielectrics with porous structures or high dielectric constants have been designed to improve the sensitivity of capacitive pressure sensors (CPSs), but this strategy has only been effective for the low-pressure range. Here, a hierarchical gradient hybrid dielectric, composed of low-permittivity (low-k) polydimethylsiloxane (PDMS) foam with low Young's modulus (low-E) and high-permittivity (high-k) MWCNT/PDMS foam with high Young's modulus (high-E), is designed to develop a CPS for monitoring biosignals over a wide force range. The foam-like structure with hybrid permittivity (low-k + high-k) is facilitated to improve the sensitivity, while the hierarchical structure with gradient Young's modulus (low-E + high-E) contributes to broadening the pressure sensing range. With the hierarchical gradient hybrid structure, the flexible pressure sensor achieves an enhanced sensitivity of 2.155 kPa-1, a wide pressure range (up to 500 kPa), a minimum detection limit (50 Pa), and an excellent durability (>2500 cycles). As a demonstration, a venous thrombosis simulation and smart insole system are established to monitor venous blood clots and plantar pressures, respectively, which reveal potential applications in wearable medicine, sports health prediction, athlete training, and sports equipment design.

A facile method for cross-linking of methacrylated wood fibers for engineered wood composites

Chemical modifications are widely used to enhance the properties of wood composites and create a strong bonding mechanism for enhancing the dimensional stability, water resistance as well as decreasing carcinogenic formaldehyde emission. Esterification is the most-known modification way to enhance the durability of wood composites, but it does not improve mechanical performance. In this work, we demonstrated a two-step, easy and quick wood surface modification strategy based on microwave heating and UV crosslinking. Firstly, the fiber surface was reacted with methacrylic anhydride, then using methacrylated groups on wood, the fibers are covalently linked. As a proof-of-concept the fibers cross-linked within five minutes under UV radiation using benzophenone solution. Then, the effect of crosslinked wood fiber on the properties of mechanical and swelling of fiberboard were studied. Using SEM, FTIR-ATR, and swelling tests, we investigated the wood-based products' reaction mechanism, morphology, and internal bonding strength. The chemical cross-linking gives stronger bonding, compared to hydrogen bonding, between fibers even in wet conditions, resulting in a cross-linked foam-like structure. Also, wood panels were fabricated, compared to unmodified fibers, the internal bond strength and dimensional stability of fiberboards increased slightly. Overall, these results show that chemical cross-linking of wood fibers can be a fast and promising way to produce multi-functional wood composites.

Incorporating Conducting PEDOT between Graphene Films for Stable Capacitive Energy Storage

Suppressing sheets stacking of graphene oxide (GO) films by introducing conductive polymers proves to be an effective way to develop graphene-based electrodes for electrochemical energy storage. This work reports a facile a method for the preparation of poly(3,4-ethylenedioxythiophene)/GO (PEDOT/GO) hybrid films by incorporating poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) between GO sheets. The subsequent dissolution of partial PSS substantially promotes the ion diffusion kinetics and simultaneously enhances film conductivity up to 931 S m–1. It has a specific capacitance of 210 F g–1 and retains 98% of its capacitance after 10 000 cycles. Further reduction of PEDOT/GO film in hydrazine vapor converts GO to chemically reduced graphene oxides (rGO) and simultaneously expands the compact film into a foam-like structure. Due to more opened electrochemically active sites and favorable ion pathways, the enhanced capacitive performance including larger specific performances of 257 F g–1, higher rate capability of 54% in 0.2–10 A g–1, and superior cycling stability with 97% capacitance preservation over 10 000 cycles has been achieved for the PEDOT/rGO film. An all-solid-state capacitor assembled with PEDOT/rGO films also demonstrates good capacitive performance and satisfactory flexibility at large bending angles.

Simple synthesis of copper/MXene/polyacrylamide hydrogel catalyst for 4-nitrophenol reduction

• A non-noble copper/MXene/polyacrylamide hydrogel was designed. • The hydrogel was synthesized by in-situ polymerization and self-reduction methods. • The hydrogel catalyst had superior catalytic activity for 4-nitrophenol reduction. • The hydrogel catalyst with foam-like structure can be simply recycled. Noble metal-based catalysts are often used in industrial catalytic reactions. However, the high price hinders their practical application. Herein, a novel Copper/MXene/polyacrylamide hydrogel catalyst is synthesized via in-situ polymerization and self-reduction method. We use Copper (Cu) as catalytic species, two-dimensional transition metal carbides (MXene) as electron transfer medium, and porous polyacrylamide (PAM) as adsorbent for designing this non-noble hydrogel catalyst. The electron transfer and adsorption capacity are improved by the synergy effects of Cu/MXene/PAM, and thus the composite catalyst for 4-nitrophenol reduction shows high catalytic activity. It is impressive that this foam-like hydrogel catalyst can be easily separated and reused many times, which has potential application for industrial catalysis.

Formation of a CoMn-Layered Double Hydroxide/Graphite Supercapacitor by a Single Electrochemical Step.

Hybrid electric storage systems that combine capacitive and faradaic materials need to be well designed to benefit from the advantages of batteries and supercapacitors. The ultimate capacitive material is graphite (GR), yet high capacitance is usually not achieved due to restacking of its sheets. Therefore, an appealing approach to achieve high power and energy systems is to embed a faradaic 2D material in between the graphite sheets. Here, a simple one-step approach was developed, whereby a faradaic material [layered double hydroxide (LDH)] was electrochemically formed inside electrochemically exfoliated graphite. Specifically, GR was exfoliated under negative potentials by CoII and, in the presence of MnII , formed GR-CoMn-LDH, which exhibited a high areal capacitance and energy density. The high areal capacitance was attributed to the exfoliation of the graphite at very negative potentials to form a 3D foam-like structure driven by hydrogen evolution as well as the deposition of CoMn-LDH due to hydroxide ion generation inside the GR sheets. The ratio between the CoII and MnII in the CoMn-LDH was optimized and analyzed, and the electrochemical performance was studied. Analysis of a cross-section of the GR-CoMn-LDH confirmed the deposition of LDH inside the GR layers. The areal capacitance of the electrode was 186 mF cm-2 at a scan rate of 2 mV s-1 . Finally, an asymmetric supercapacitor was assembled with GR-CoMn-LDH and exfoliated graphite as the positive and negative electrodes, respectively, yielding an energy density of 96.1 μWh cm-3 and a power density of 5 mW cm-3 .

Hexagonal Voronoi pattern detected in the microstructural design of the echinoid skeleton.

Repeated polygonal patterns are pervasive in natural forms and structures. These patterns provide inherent structural stability while optimizing strength-per-weight and minimizing construction costs. In echinoids (sea urchins), a visible regularity can be found in the endoskeleton, consisting of a lightweight and resistant micro-trabecular meshwork (stereom). This foam-like structure follows an intrinsic geometrical pattern that has never been investigated. This study aims to analyse and describe it by focusing on the boss of tubercles—spine attachment sites subject to strong mechanical stresses—in the common sea urchin Paracentrotus lividus. The boss microstructure was identified as a Voronoi construction characterized by 82% concordance to the computed Voronoi models, a prevalence of hexagonal polygons, and a regularly organized seed distribution. This pattern is interpreted as an evolutionary solution for the construction of the echinoid skeleton using a lightweight microstructural design that optimizes the trabecular arrangement, maximizes the structural strength and minimizes the metabolic costs of secreting calcitic stereom. Hence, this identification is particularly valuable to improve the understanding of the mechanical function of the stereom as well as to effectively model and reconstruct similar structures in view of future applications in biomimetic technologies and designs.

Low-Temperature Selective NO Reduction by CO over Copper-Manganese Oxide Spinels

Selective catalytic reduction of NO with CO (CO-SCR) has been suggested as an attractive and promising technology for removing NO and CO simultaneously from flue gas. Manganese-copper spinels are a promising CO−SCR material because of the high stability and redox properties of the spinel structure. Here, we synthesized CuxMn3−xO4 spinel by a citrate-based modified pechini method combining CuO and MnOx, controlling the molar Cu/Mn concentrations. All the samples were characterized by SEM, EDX, XRD, TEM, H2−TPR, XPS and nitrogen adsorption measurements. The Cu1.5Mn1.5O4 catalyst exhibits 100% NO conversion and 53.3% CO conversion at 200 °C. The CuxMn3−xO4 catalyst with Cu-O-Mn structure has a high content of high valence Mn, and the high mass transfer characteristics of the foam-like structure together promoted the reaction performance. The CO-SCR catalytic performance of Cu was related to the spinel structure with the high ratio of Mn4+/Mn, the synergistic effect between the two kinds of metal oxides and the multistage porous structure.

Study on the photothermal performance of polytetrafluoroethylene-based evaporation interface with solar-driven enhanced by graphite-clay

Interface evaporation by solar-driven was a thermal desalination method that offered high efficiency and energy-saving. The photo-thermal conversion efficiency of the interface evaporation device by solar-driven could be effectively improved by increasing the optical absorption capacity (a) and wetting capacity (MI) of the evaporation interface simultaneously. In this study, the photothermal performance of the solar-driven interface evaporation device was enhanced by graphite-clay. And an improved evaluation idea and a corresponding calculation method for photothermal performance were proposed. The morphology and hydrophilicity of the solar-driven polytetrafluoroethylene-based evaporation interface (GC-PTFE) enhanced by graphite-clay were characterized. A regression model of the contribution rate (ηfh) of graphite-clay on the photo-thermal conversion efficiency of the GC-PTFE unit was constructed. The results showed that the GC-PTFE (HB) presented a loose foam-like micron-level microporous structure, and all the GC-PTFEs offered hydrophilicity. The maximum theoretical value and corresponding prediction error of ηfh were 87.88% and 0.97%, respectively. The rejection rate of GC-PTFE for all measured ions was more than or equal to 99.95%. This study had an important guiding significance for optimizing the key structural parameters and evaluation system of photothermal performance of the GC-PTFE unit.

Micro-diamond assisted bidirectional tuning of thermal conductivity in multifunctional graphene nanoplatelets/nanofibrillated cellulose films

Environmentally friendly thermal interface materials (TIMs) with bidirectional high thermal conductivities have aroused considerable interests for addressing the heat dissipation issue in integrated circuits. Although graphene-based TIMs exhibit excellent in-plane thermal conductive performance, their through-plane thermal conductivity is commonly less than 3 Wm−1K−1 owing to the vast interfacial phonon scattering, significantly limiting their practical applications. In this study, a strategy aimed at building TIMs with controllable heat transfer pathways both along the in-plane and through-plane directions is proposed by incorporating micron-diamonds (MDs) in graphene nanoplatelets/nanofibrillated cellulose (GNPs/NFC) composite film via a facile and green self-assembly method. The morphology of the obtained MDs@GNPs/NFC composite film can be precisely tailored from a hierarchical structure to a 3D solid foam-like structure to tailor heat transfer paths. By adjusting the loading and particle size of MDs, a through-plane thermal conductivity of 8.85 Wm−1K−1 was achieved accompanied with a simultaneously high in-plane thermal conductivity of 32.01 Wm−1K−1. The excellent bidirectional thermal conductive performance is integrated with high-efficiency Joule heating capability, outstanding nonflammability, as well as superior electromagnetic shielding performance, showing a promising future in advanced electronic devices.