Formation Of 3D Network Research Articles

Construction of tree-ring mimetic 3D networks in polyvinyl alcohol/boron nitride composites for enhanced thermal management and mechanical properties

Constructing a three-dimensional (3D) filler network in polymer thermal interface materials (TIMs) is crucial for enhancing thermal conductivity and mechanical properties. However, the discontinuous and loose network of fillers are one of the main reasons hindering the joint improvement of thermal conductivity and mechanical properties. The construction of a regular and dense 3D continuous filler network remains a significant challenge. In this study, an innovative bidirectional freezing technique was designed to create a polyvinyl alcohol (PVA)/boron nitride (BN) composite with a tree-ring-like 3D network. This technique promotes the formation of 3D network consisting of long-range lamellar BN layers with a tree-ring-like structure by controlling the nucleation and growth of ice crystals along the bidirectional temperature gradient induced by a polytetrafluoroethylene (PTFE) cone. The resulting PVA/BN composite exhibits high thermal conductivity (6.25 W/m·K) due to the lower interfacial thermal resistance between fillers (1.271 × 10−7 K m2/W), and an enhanced tensile strength of 41.71 MPa, which is attributed to the regular and dense BN network. This study presents a feasible strategy for constructing a 3D continuous network structure in polymer-based TIMs, paving the way for advancements in thermal management solutions.

Fabrication of fire-retarded epoxy asphalt composites with compatibilization and toughening for road tunnel pavements

Although epoxy asphalt (EA) mixtures have been widely used for the pavement in tunnels, it was limited by its flammability, poor compatibility and low mechanical property. To solve the above problems, a compatibilized and toughening flame retardant (ESO-AA-DOPO) was prepared via the epoxidized soybean oil (ESO), arachidonic acid (AA) and 9,10-Dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO). The presence of ESO-AA-DOPO significantly improved the flame retardancy, in which passing the UL-94 V-2 rating. The peak heat release rate (PHRR) reducing by 46.2 % for EA/40A-ESO-AA-DOPO composites comparing to that of pure EA. The analysis of char residue confirmed that the catalytic formation of dense and continuous char layer residue with good thermal oxidation stability originating from the ESO-AA-DOPO. The initial stage viscosity of ESO-AA-DOPO modified EA was lower than that of pure EA. Under the action of aliphatic epoxy resin and double bond, the molecular chain of epoxy resin presented a network structure, the base asphalt was divided into micelles, and the overall distribution of EA system was a 3D networks “sea-island”, which ensuring the increase in the glass transition temperature (Tg) of the EA system. The tensile strength and elongation at break of EA/40A-ESO-AA-DOPO composites were 123 % and 207 % higher than those of pure EA attributing to the improved compatibility and the formation of 3D networks “sea-island” structure.

Synthetic biodegradable microporous hydrogels for in vitro 3D culture of functional human bone cell networks

Generating 3D bone cell networks in vitro that mimic the dynamic process during early bone formation remains challenging. Here, we report a synthetic biodegradable microporous hydrogel for efficient formation of 3D networks from human primary cells, analysis of cell-secreted extracellular matrix (ECM) and microfluidic integration. Using polymerization-induced phase separation, we demonstrate dynamic in situ formation of microporosity (5–20 µm) within matrix metalloproteinase-degradable polyethylene glycol hydrogels in the presence of living cells. Pore formation is triggered by thiol-Michael-addition crosslinking of a viscous precursor solution supplemented with hyaluronic acid and dextran. The resulting microporous architecture can be fine-tuned by adjusting the concentration and molecular weight of dextran. After encapsulation in microporous hydrogels, human mesenchymal stromal cells and osteoblasts spread rapidly and form 3D networks within 24 hours. We demonstrate that matrix degradability controls cell-matrix remodeling, osteogenic differentiation, and deposition of ECM proteins such as collagen. Finally, we report microfluidic integration and proof-of-concept osteogenic differentiation of 3D cell networks under perfusion on chip. Altogether, this work introduces a synthetic microporous hydrogel to efficiently differentiate 3D human bone cell networks, facilitating future in vitro studies on early bone development.

Guiding bone cell network formation in 3D via photosensitized two-photon ablation

A long-standing challenge in skeletal tissue engineering is to reconstruct a three-dimensionally (3D) interconnected bone cell network in vitro that mimics the native bone microarchitecture. While conventional hydrogels are extensively used in studying bone cell behavior in vitro, current techniques lack the precision to manipulate the complex pericellular environment found in bone. The goal of this study is to guide single bone cells to form a 3D network in vitro via photosensitized two-photon ablation of microchannels in gelatin methacryloyl (GelMA) hydrogels. A water-soluble two-photon photosensitizer (P2CK) was added to soft GelMA hydrogels to enhance the ablation efficiency. Remarkably, adding 0.5 mM P2CK reduced the energy dosage threshold five-fold compared to untreated controls, enabling more cell-compatible ablation. By employing low-energy ablation (100 J/cm2) with a grid pattern of 1 µm wide and 30 µm deep microchannels, we induced dendritic outgrowth in human mesenchymal stem cells (hMSC). After 7 days, the cells successfully utilized the microchannels and formed a 3D network. Our findings reveal that cellular viability after low-energy ablation was comparable to unablated controls, whereas high-energy ablation (500 J/cm2) resulted in 42 % cell death. Low-energy grid ablation significantly promoted network formation and >40 µm long protrusion outgrowth. While the broad-spectrum matrix metalloproteinase inhibitor (GM6001) reduced cell spreading by inhibiting matrix degradation, cells invaded the microchannel grid with long protrusions. Collectively, these results emphasize the potential of photosensitized two-photon hydrogel ablation as a high-precision tool for laser-guided biofabrication of 3D cellular networks in vitro. Statement of SignificanceThe inaccessible nature of osteocyte networks in bones renders fundamental research on skeletal biology a major challenge. This limit is partly due to the lack of high-resolution tools that can manipulate the pericellular environment in 3D cultures in vitro. To create bone-like cellular networks, we employ a two-photon laser in combination with a two-photon sensitizer to erode microchannels with low laser dosages into GelMA hydrogels. By providing a grid of microchannels, the cells self-organized into a 3D interconnected network within days. Laser-guided formation of 3D networks from single cells at micron-scale resolution is demonstrated for the first time. In future, we envisage in vitro generation of bone cell networks with user-dictated morphologies for both fundamental and translational bone research.

Network Bursts in 3D Neuron Clusters Cultured on Microcontact-Printed Substrates.

Microcontact printing (CP) is widely used to guide neurons to form 2D networks for neuroscience research. However, it is still difficult to establish 3D neuronal cultures on the CP substrate even though 3D neuronal structures are able to recapitulate critical aspects of native tissue. Here, we demonstrate that the reduced cell-substrate adhesion caused by the CP substrate could conveniently facilitate the aggregate formation of large-scale 3D neuron cluster networks. Furthermore, based on the quantitative analysis of the calcium activity of the resulting cluster networks, the effect of cell seeding density and local restriction of the CP substrate on network dynamics was investigated in detail. The results revealed that cell aggregation degree, rather than cell number, could take on the main role of the generation of synchronized network-wide calcium oscillation (network bursts) in the 3D neuron cluster networks. This finding may provide new insights for easy and cell-saving construction of in vitro 3D pathological models of epilepsy, and into deciphering the onset and evolution of network bursts in developmental nerve systems.

Structural characterization and photoelectrochemistry of coordination polymer of Pb(II)‐naphthyl‐isonicotinohydrazide Schiff base

An organic–inorganic hybrid Pb(II)‐based 1D coordination polymer, {[Pb(NSB)NO3.DMF]}n (CP) (H‐NSB = isonicotinic acid (2‐hydroxy‐naphthalen‐1‐ylmethylene)‐hydrazide; DMF = N,N‐dimethylformamide), is structurally characterized by single crystal X‐ray diffraction measurement and other spectroscopic data. The structure shows that the ligand, H‐NSB serves as a monoanionic tetradentate N2O2 chelating linker of μ3‐κN,κO;κO,N,O type, where κO (phenolato‐O) brings two Pb(II) centres together and the tridentate NO2 unit chelates (κO,N,O) with one Pb(II) unit followed by its pyridyl‐N links (κN) with nearest Pb(II) centre for propagating as a seven coordinated distorted pentagonal bi‐pyramidal PbO5N2 core (one O donor comes from DMF and another O from NO3−). Thus, 1D chain is constructed that is thermally stable. The noncovalent interactions (π…π, H‐bonding and C‐H…π) amongst the 1D chains make supramolecular 3D architecture. The Hirshfeld surface analysis approves the existence of several noncovalent interactions for the formation of 3D network. The reasonable band gap of 3.04 eV for the CP lies in the semiconducting region, which simulates fabrication of photoelectrochemical device with high magnitude of photocurrent (current density: ~2.5 μA cm−2). Mott–Schottky analysis indicates the n‐type semiconducting behaviour, and chronoamperometry plot also shows the stability of the material against photo corrosion. Present elucidation would decipher an encouraging pathway for harvesting next‐generation energy resources based on a novel Pb(II)‐naphthyl‐isonicotinohydrazide Schiff base‐based CP.

Role of Cerium Doping in Petal‐Like NiO Grown Directly over Ni Foam for Enhancing the Super‐Capacitive Behaviour

AbstractWe have synthesized petal‐like structure of cerium doped nickel oxide over the nickel foam using a hydrothermal method at 120 °C. The variation of the doping concentration of cerium from 1–7 mol% was studied to improve the capacitive behaviour. X‐ray diffraction spectroscopy indicates the presence of the NiO phase without any impurities. Field emission scanning electron microscopy shows formation of 3D network by the interconnection of 2D petals morphology. Further, X‐Ray data has been supported by the Raman scattering measurements. X‐ray photoelectron spectroscopy data confirmed the presence of NiO along with traces of Ce3+ which categorically indicate successful doping of Ce3+ in NiO matrix. The electrochemical analysis shows the pseudo‐capacitive behaviour with a specific capacitance of 794.58 F/g at 5 mV/s scan rate. It also shows the cyclic stability of 89.23 % after 800 cycles at a scan rate of 10 mV/s. Electrochemical impedance spectroscopy was carried out to investigate the involved charge transfer kinetics. The 5 mol% doping of cerium into the NiO crystal shows low resistance which provides a shortened path for the charge transfer. It helps to improve the electrochemical behaviour. Thus, the results have shown that cerium doping in NiO can improve the electrochemical performance of the system.

Improved charge transport through 2D framework in fully condensed carbon nitride for efficient photocatalytic hydrogen production

The 1D molecular structure of traditional graphitic carbon nitride (GCN) leads to the space-confined transport of charge carriers along the chains and prohibits transport across the chains. Therefore, the formation of 2D network which can provide more convenient transfer paths is of great desirable. In this work, a fully condensed carbon nitride with the real 2D framework was successfully developed by post-calcining 1D GCN in a LiCl/KCl molten salt. The newly formed 2D molecular structure significantly promoted the charge transfer and separation, resulting in remarkably enhanced photocatalytic hydrogen production activity. Moreover, N-doped graphene quantum dots (NGQDs) incorporation can be simultaneously realized via the simple one step “co-dissolution and recrystallization” method. Especially, the as-prepared 2D-CN/NGQDs sample presents a further increased photocatalytic hydrogen evolution rate up to about 30 times that of pristine GCN. The apparent quantum efficiency (AQE) for H2 evolution of 2D-CN/NGQDs reaches 36 % at 420 nm.

Integration of single-cell transcriptomes and biological function reveals distinct behavioral patterns in bone marrow endothelium

Heterogeneity of endothelial cell (EC) populations reflects their diverse functions in maintaining tissue’s homeostasis. However, their phenotypic, molecular, and functional properties are not entirely mapped. We use the Tie2-CreERT2;Rosa26-tdTomato reporter mouse to trace, profile, and cultivate primary ECs from different organs. As paradigm platform, we use this strategy to study bone marrow endothelial cells (BMECs). Single-cell mRNA sequencing of primary BMECs reveals that their diversity and native molecular signatures is transitorily preserved in an ex vivo culture that conserves key cell-to-cell microenvironment interactions. Macrophages sustain BMEC cellular diversity and expansion and preserve sinusoidal-like BMECs ex vivo. Endomucin expression discriminates BMECs in populations exhibiting mutually exclusive properties and distinct sinusoidal/arterial and tip/stalk signatures. In contrast to arterial-like, sinusoidal-like BMECs are short-lived, form 2D-networks, contribute to in vivo angiogenesis, and support hematopoietic stem/progenitor cells in vitro. This platform can be extended to other organs’ ECs to decode mechanistic information and explore therapeutics.

Effect of bonding on the structure and properties of nanocellulose films

In this study, cellulose nanofibers (CNF) were obtained by chemical pretreatment using a rubberwood substrate. Different forms of drying were used to prepare three CNF film variants. Each of the films was rehydrated and hot-pressed to introduce more hydrogen bonds, and the films were characterized in terms of density and porosity, micromorphology, and mechanical properties. The mechanical properties of the films improved substantially after rehydration and hot-press drying. The tensile strengths of the films increased to approximately two to three times that of the original CNF films. These results with micromorphological observations suggest that adjusting the water content during CNF drying can significantly improve the formation of 3D networks in the films, thus imparting higher hydrogen bonding content to the films and improving the mechanical properties of the substrates. This study provides a theoretical basis for the formation of high-strength materials through water molecule-induced assembly and broadens the application of biomass cellulose materials in emerging fields.

PANI/CFO@CNTs ternary composite system for EMI shielding applications

With the advancement of modern communication technologies and the internet of things (IoT), the manufacturing of light, flexible, and high-performance electromagnetic interference (EMI) shields is imperative to minimize harmful effects of radiation on humans and electronic devices. Lightweight ferrites/carbon allotropes/polymer-based ternary composites with abundant interfaces are potential candidates for excellent absorption materials due to their high attenuation capability and impedance matching. We report EMI shielding properties of composites made of carbon nanotubes (CNTs) decorated with cobalt ferrite (CFO) nanoparticles and coated with polyaniline (PANI). The electromagnetic properties of the CFO@CNTs binary composite have been fine-tuned by varying the weight percentage of CNTs. The formation of CFO, CNTs and emeraldine form of PANI was confirmed by XRD and Raman spectroscopy. Transmission electron microscopy (TEM) revealed uniform attachment of CFO nanoparticles to the walls of CNTs, formation of 3D networks in the CFO@CNTs binary composite and its effective encapsulation by PANI. Benefiting from the controllable composition, 3D networking, porous structure of PANI, and strong complementary effect between CFO and CNTs (source of magnetic and dielectric losses), the PANI/CFO@CNTs ternary composite exhibited superior EMI shielding characteristics with a total shielding effectiveness of 16.80 dB corresponding to 97.90 % attenuation at a thickness of 2 mm. Considering the excellent EMI shielding properties, PANI/CFO@CNTs ternary composites can be employed as high-performance EMI shields.

Recovery of structural extracellular polymeric substances (sEPS) from aerobic granular sludge: Insights on biopolymers characterization and hydrogel properties for potential applications

Nowadays, wastewater treatment plants (WWTPs) are transforming into water resource recovery facilities (WRRFs) where the resource recovery from waste streams is pivotal. Aerobic granular sludge (AGS) is a novel technology applied for wastewater treatment. Extracellular polymeric substances (EPS) secreted by microorganisms promote the aggregation of bacterial cells into AGS and the structural fraction of EPS (sEPS) is responsible for the mechanical properties of AGS. sEPS can be extracted and recovered from waste AGS by physico-chemical methods and its characterization is to date of relevant concern to understand the properties in the perspective of potential applications. This study reports on: characterization of sEPS extracted and recovered from AGS; - formation and characterization of sEPS-based hydrogels. Briefly, sEPS were extracted by a thermo-alkaline process followed by an acidic precipitation. sEPS-based hydrogels were formed by a cross-linking process with a 2.5% w/w CaCl2 solution. The following key-findings can be drawn: i) hydrogels can be formed starting from 1% w/w sEPS on, by diffusion of Ca2+ into sEPS network; ii) the Ca/C molar ratio of hydrogels decreased with increasing concentration of sEPS from 1 to 10% w/w; iii) the thermogravimetric and spectroscopic behaviours of sEPS show that the cross-linking reaction mainly involves the polysaccharidic fraction of biopolymers; iv) water-holding capacity up to 99 gH2O/gsEPS was registered for 1% w/w sEPS-based hydrogels, suggesting applications in several industrial sectors (i.e. chemical, paper, textile, agronomic, etc.); v) rheological results highlighted a solid-like behaviour (G’≫G”) of sEPS-based hydrogels. The power-law fitting of G’ vs. sEPS concentration suggests that the expansion of the sEPS network during cross-linking occurs through a percolative mechanism involving the initial formation of sEPS oligomers clusters followed by their interconnection towards the formation of 3D network. These findings provide additional information about the mechanisms of sEPS-based hydrogel formation and reveal the peculiar physico-chemical characteristics of sEPS which nowadays are increasingly gaining interest in the context of resource recovery.

Mesitylene Tribenzoic Acid as a Linker for Novel Zn/Cd Metal-Organic Frameworks.

Three new Metal-Organic Frameworks, containing mesitylene tribenzoic acid as a linker and zinc (1) or cadmium as metals (2,3), were synthesized through solvothermal reactions, using DMF/ethanol/water as solvents, at temperatures of 80 °C (structures 1 and 3) and 120 °C (structure 2). Following single-crystal X-ray diffraction, it was found that 1 and 3 crystallize in the P21/c and C2/c space groups and form 2D networks, while 2 crystallizes in the Fdd2 space group, forming a 3D network. All three frameworks, upon heating, were found to be stable up to 350 °C. N2 sorption isotherms revealed that 1 displays a BET area of 906 m2/g. Moreover, the porosity of this framework is still present after five cycles of sorption/desorption, with a reduction of 14% of the BET area, down to 784 m2/g, after the fifth cycle. The CO2 loading capacity of 1 was found to be 2.9 mmol/g at 0 °C.

Different Impact of Suspended Al2O3 Nanoparticles on Microbial Communities: Formation of 2D-Networks (Without Humic Acids) or 3D-Colonies (With Humic Acids).

The use of metal-based and, particularly, Al2O3 nanoparticles (Al2O3-NP) for diverse purposes is exponentially growing. However, the growth of such promissory market is not accompanied by a parallel extensive investigation related to the impact of this pollution on groundwater and biological systems. Pseudomonas species, ubiquitous, environmentally critical microbes, frequently respond to stress conditions with diverse strategies that generally include extracellular polymeric substances (EPS) formation. The aim of this study is to report that changes in the aqueous environment, particularly, the addition of Al2O3-NP without and with humic acids, induce different adaptive strategies of Pseudomonasaeruginosa early biofilms. To this purpose, early biofilms were incubated in diluted culture media without (control) and with Al2O3-NP, and with humic acids (HA-control, HA-Al2O3-NP) for 24h. 3D colonies with EPS strings and isolated bacteria in their surroundings were detected in the control biofilms. Unlikely, an unusual adaptive behaviour was developed in the presence of Al2O3-NP. Bacteria opt to disassemble the 3D arrangements and to implement a 2D network promoting morphological and size changes of bacterial cells (small coccoid shapes). Remarkably, this strategy allows their temporarily non-EPS-depending survival without decreasing the number of cells. This behaviour was not observed with ZnO-NP, HA-Al2O3-NP, or HA-ZnO-NP. Physicochemical analysis revealed that HA were adsorbed on Al2O3-NP and promoted the Al(III) ions complexation. This supports the hypothesis that the reduction of toxicity of Al ions and the 3D colony formation in the presence of HA-Al2O3-NP is promoted by the complexation of the metal ions with HA components.

Sunflower Oil–Beeswax Oleogels Are Promising Frying Medium for Potato Strips

AbstractSunflower oil–beeswax oleogels at 3% (BWO‐3) and 8% (BWO‐8) organogelator concentration are prepared to evaluate oleogels as frying medium for potato strip frying against commercial sunflower oil (SO). Rheological and thermal analyses of oleogels prove that the samples are fully solid (20±3 °C) and totally liquid (180 °C), and thermoreversible. Fresh and used (after frying) fat analyses show that free fatty acidity (FFA), peroxide value (PV) and total polar materials (TPM) are enhanced in all samples at the 7th h, but the relative enhancement levels are lower in oleogel samples. Potato strips fried in oleogels absorb significantly less oil (11.97% and 12.07%) than the control sample (15.20%). Potatoes fried in oleogels are also more bright and yellower than the control sample. Textural profile of the fried potatoes indicates that the samples fried in oleogels are harder, springier, and gummier than that of the control sample. Sensory analysis shows that oleogel fried potatoes get higher sensory scores. Also, overall acceptability of potatoes fried in BWO‐8 sample is the highest (8.50) among all. The prepared oleogels are found quite promising frying medium in this study. Further studies with other types of oleogels in extended period frying of various foods are suggested.Practical applications: The development of innovative frying techniques to produce healthier products with lower fat and calorie values are still a remarkable research area. Oleogelation is an emerging strategy used for solid‐like oil designing and based on the formation of 3D networks by the addition of organogelators. Oleogelation is accepted as a healthy strategy to structure liquid oils into solid consistency, and oleogels have great edible applications in processed foods, and can be used as a frying medium. This work can guide the use of sunflower oil–beeswax oleogels as a frying medium and allow the development of more healthy fried snacks.

In situ dual crosslinking strategy to improve the physico-chemical properties of thermoplastic starch

This study is focused on enhancing the stability of mechanical and chemical properties of thermoplastic starch (TPS) by dual crosslinking strategy through melt processing conditions. The dually crosslinked TPS was prepared by in situ reaction of starch, glycerol, and epichlorohydrin (ECH), resulting in both noncovalent and covalent bond formation. The TPS was characterized by tensile testing, dynamic mechanical analysis (DMTA), rheology, and solubility in water. A substantial increase in tensile strength, Young's modulus, insoluble portion, and stability in water for dually crosslinked TPS was observed in comparison with conventional TPS. The rheology results indicated that the ECH induced the formation of 3D networks and significantly limited the chain mobility of the melted TPS, resulting in an extended relaxation process, which was also verified by DMTA. The suggested strategy avoids any chemical modification pretreatment of starch for introducing covalent bonds into TPS before one-step mixing using the melt processing technique.

Study 3D Endothelial Cell Network Formation under Various Oxygen Microenvironment and Hydrogel Composition Combinations Using Upside-Down Microfluidic Devices.

Formation of 3D networks is a crucial process for endothelial cells during development of primary blood vessels under both normal and pathological conditions. In order to investigate effects of oxygen microenvironment and matrix composition on the 3D network formation, an upside-down microfluidic cell culture device capable of generating oxygen gradients is developed in this paper. In cell experiments, network formation of human umbilical vein endothelial cells (HUVECs) within fibrinogen-based hydrogels with different concentrations of hyaluronic acid (HA) is systematically studied. In addition, five different oxygen microenvironments (uniform normoxia, 5%, and 1% O2 ; oxygen gradients under normoxia and 5% O2 ) are also applied for the cell culture. The generated oxygen gradients are characterized based on fluorescence lifetime measurements. The experimental results show increased 3D cell network length when the cells are cultured under the oxygen gradients within the hydrogels with the HA addition suggesting their roles in promoting network formation. Furthermore, the formed networks tend to align along the direction of the oxygen gradients indicating the presence of gradient-driven cellular response. The results demonstrate that the developed upside-down microfluidic device can provide an advanced platform to investigate 3D cell culture under the controlled oxygen microenvironments for various biomedical studies in vitro.

Designed assembly of Ni/MAX (Ti3AlC2) and porous graphene-based asymmetric electrodes for capacitive deionization of multivalent ions

The contamination of aquatic ecosystems by fluoride and heavy metal ions constitute an environmental hazard and has been proven to be harmful to human health. This study explores the feasibility of using asymmetric capacitive deionization (CDI) electrodes to remove such toxic ions from wastewater. An asymmetric CDI cell was fabricated using 2D Ni/MAX as an anode and 3D porous reduced graphene oxide (pRGO) as a cathode for the electrosorption of F−, Pb2+, and As(III) ions. A simple microwave process was used for the synthesis of Ni/MAX composite using fish sperm DNA (f-DNA) as a cross-linker between MAX nanosheets (NSs) and the metallic Ni nanoparticles (NPs). Further, pRGO anode was prepared through effective reduction of RGO using lemon juice as green reducing agent with the assist of f-DNA as a structure-directing agent for the formation of 3D network. With this tailored nanoarchitecture, pRGO and Ni/MAX electrodes exhibited a high specific capacitance of 760 and 385 F g−1, respectively. The fabricated Ni/MAX and pRGO based CDI system demonstrated a high electrosorption capacity of 68, 76, and 51 mg g−1 for the monovalent F−, divalent Pb2+, and trivalent As(III) ions at 1.4 V in neutral pH. Furthermore, Ni/MAX//pRGO system was successfully applied for the removal of total F(T), Pb(T), and As(T) ions from real industrial wastewater and contaminated groundwater. The present findings indicate that the fabricated Ni/MAX//pRGO electrode has excellent electrochemical properties that can be exploited for the removal of anionic and cationic metal ions from aqueous solutions in a CDI based system.

2D and 3D Ruthenium Nanoparticle Covalent Assemblies for Phenyl Acetylene Hydrogenation

The bottom‐up covalent assembly of metallic nanoparticles (NP) represents one of the innovative tools in nanotechnology to build functional heterostructures, with the resulting assemblies showing superior collective properties over the individual NP for a broad range of applications. The ability to control the dimensionality of the assembly is one of the major challenges in designing and understanding these advanced materials. Here, two new organic linkers were used as building blocks in order to guide the organization of Ru NP into two‐ or three‐dimensional covalent assemblies. The use of a hexa‐adduct functionalized C60 leads to the formation of 3D networks of 2.2 nm Ru NP presenting an interparticle distance of 3.0 nm, and the use of a planar carboxylic acid triphenylene derivative allows the synthesis of 2D networks of 1.9 nm Ru NP with an interparticle distance of 3.1 nm. The Ru NP networks were found to be active catalysts for the selective hydrogenation of phenylacetylene, reaching good selectivity toward styrene. Overall, we demonstrated that catalyst performances are significantly affected by the dimensionality (2D vs. 3D) of the heterostructures, which can be rationalize based on confinement effects.

Enhanced thermal conductivity by constructing 3D-networks in poly(vinylidene fluoride) composites via positively charged hexagonal boron nitride and silica coated carbon nanotubes

Thermal-conductive yet electrical-insulating polymer composites with outstanding mechanical properties have attracted increasing attention in the electronic field. Herein, three-dimensional (3D) thermal-conductive networks were built in PVDF matrix via electrostatic repulsion of positively charged hexagonal boron nitride (m-hBN) and bridging of silica-coated carbon nanotubes (MWCNTs-SiO2). The results indicated that 25 wt% m-hBN/MWCNTs-SiO2/PVDF presented fascinating characteristics: a high thermal conductivity of 1.51 W/(m·K) and an excellent tensile strength of 55.02 MPa, with the enhancements of 586% and 25% respectively compared to pure PVDF; besides, superior dielectric properties and electrical insulation were obtained, with dielectric constant of 4.95, dielectric loss tangent of 0.14 at 1 MHz, and volume resistivity of 3.45 × 1012 Ω·cm. The Effective Medium Approximation (EMA) model revealed that the formation of 3D-networks could significantly decrease thermal resistance and promote phonon transmission. The outstanding heat dissipation capability of m-hBN/MWCNTs-SiO2/PVDF was verified by infrared imaging test, indicating its potential applications for thermal management.