Interfacial Connection Research Articles

Impact of Dilute DIO Additive on Local Microstructure of Fluorinated, pNDI-Based Polymer Solar Cells.

The performance of all-polymer solar cells is often enhanced by incorporating solvent additives during solution processing. In particular, blends based on the model all-polymer system PBDBT:N2200 have been shown to have increased short-circuit current and fill factor when processed with dilute diiodooctane (DIO). However, the morphological mechanism that drives the increase in performance is often not well understood due to limitations in common characterization techniques. In this study, it is shown that a combination of X-ray techniques with cryogenic high-resolution transmission electron microscopy (HRTEM) analysis can provide a quantitative and spatially resolved picture of polymer chain orientation and alignment in all-polymer blends. It is found that DIO induces vertical phase separation in PBDBT-2F:F-N2200 and increases donor crystallite thickness in the pi-stacking direction leading to an acceptor-rich film surface. However, it is also shown that DIO does not disrupt the formation of face-on donor-acceptor interfaces. These findings suggest that dilute DIO primarily affects crystalline domain formation in single component regions as opposed to mixed regions; thus, dilute DIO can impact vertical charge transport pathways without sacrificing donor-acceptor interfacial connectivity.

Fabrication and High Dielectric Properties of Sandwich-Structured Ba0.6Sr0.4TiO3/Polyvinylidene Fluoride Layered Composites with Multiscale Parallel Interfaces.

Ba0.6Sr0.4TiO3/polyvinylidene fluoride (BST/PVDF) dielectric functional composites have been widely used in flexible wearable devices, capacitors, and energy storage devices. In addition to the ceramic phase type, polymer matrix type, composition, and interfacial connectivity of BST/PVDF composite materials, their morphology also significantly influences their electrical characteristics. Therefore, herein, sandwich-structured BST/PVDF layered composites were designed and prepared via tape-casting processing using different types of BST fillers [i.e., formless zero-dimensional (0D)-BST, rod-like one-dimensional (1D)-BST, and plate-like two-dimensional (2D)-BST]. The microstructures and electrical characteristics of sandwich-structured BST/PVDF composites were studied in relation to the BST morphology. The effects of the internal mechanisms of different interfacial models on the breakdown strength of BST/PVDF composites were discussed. According to our findings, unlike the 0D-BST and 1D-BST powders, 2D-BST powders form multiscale parallel interfaces in sandwich-structured composites due to their unique lamella-like morphology, which enhances the breakdown strength of sandwich-structured composites. Sandwich-structured BST/PVDF composites containing 2D-BST powders exhibit good electrical characteristics with an energy storage density of 19.71 J/cm3, an energy storage efficiency of 85.3%, a dielectric constant of 30.4 (1 kHz), a dielectric loss of 0.036 (1 kHz), and a dielectric tunability of 93.2%. This study provides a method for preparing functional composites with high dielectric tunability and high energy storage characteristics.

Seismic behavior of composite shear walls with post-casting UHPC boundary elements and CRB600H steel bars

This study investigates the seismic behavior of composite shear walls reinforced with post-casting Ultra-High Performance Concrete (UHPC) boundary elements and Colded-Rolled Ribbed Bars (CRB600H). The research aims to explore the synergistic effects of UHPC and CRB600H bars on seismic performance. Six shear wall specimens with a shear span ratio of 1.56 were subjected to cyclic loading to evaluate their failure modes, crack patterns, hysteresis behavior, stiffness degradation, ductility, residual deformation, and energy dissipation capacity. The results demonstrated that the use of CRB600H bars in boundary elements of normal concrete specimens improved post-yield stiffness and reduced residual deformation. Conversely, incorporating UHPC in boundary elements enhanced load-bearing capacity and crack control but slightly reduced ductility due to the weaker interfacial connection between UHPC and the foundation. Additionally, CRB600H bars in the web region improved load-bearing capacity while maintaining ductility comparable to HRB400 bars. The findings suggest that substituting CRB600H for HRB400 in shear-dominant regions can enhance the seismic performance of shear walls. Finally, the multi-layer shell element numerical model validated by the experimental results was encouraged to conduct parametric analysis in the future. This research supports the development of more resilient building structures by integrating high-performance materials in key structural components.

An innovative interlayer improving the interfacial connection of FeCoNiCrTi coating on copper surface

To improve the performance of copper surface, a FeCoNiCrTi high entropy alloy coating was first attempted to be prepared on copper substrate by plasma cladding. The obtained single-layer coating had a smooth and flat surface, but the interfacial connection was poor. Interfacial defect analysis results showed that the alloying elements dominated by Ti in the coating reacted with the CuO formed during the preheating process on copper surface. A large amount of TiO2 and other complex oxides were generated and distributed at the interface, which hindered the interfacial connection. After introducing a Ni60A interlayer, the interface reaction between FeCoNiCrTi alloy and copper oxide was avoided, and the inter-diffusion of elements was promoted, thus forming a good metallurgical bonding. Furthermore, due to the dilution effect of Ni60A interlayer, the performance of FeCoNiCrTi surface layer slightly decreased, but still far superior to the Ni60A coating. The microhardness of FeCoNiCrTi surface layer was about 10.7 times that of copper substrate. The wear loss of the developed coating is only 1/2 of that of the single Ni60A coating at 600 °C. This study has a great significance for extending the application of FeCoNiCrTi high entropy alloy coatings in surface strengthening on copper.

Role of pulse globulins and albumins in air-water interface and foam stabilization

Pulse protein isolates are promising substitutes for animal protein in foam preparation, but they typically are complex mixtures of multiple proteins, and the contribution of the individual proteins to the behavior of the mixture in air-water interface stabilization is largely unknown. The major protein fractions in isolates are the globulins and albumins, and this study systematically investigated the molecular properties, and interfacial and foaming properties of these two fractions for three different pulses: lentils, faba beans and chickpeas. The key parameters of these pulse proteins in air-water interface and foam stabilization were investigated by correlation analysis. Based on this, low denaturation enthalpy tends to result in both high foamability and foam stability, most likely due to a greater conformational flexibility that allows for a faster adsorption to the air-water interface, and higher degree of structural rearrangement at the interface, which increases interfacial network stiffness. For globulin-rich pulse protein fractions, vicilins and convicilins tend to introduce high surface hydrophobicity, which increases the affinity of the proteins for the interface, and increases protein-protein in-plane interactions through hydrophobic interactions, resulting in the enhancement of interfacial network connectivity and the level of network branching. These factors increase the interfacial resistance to large deformations and increase foam stability. Vicilins and convicilins also tend to have a high value of the surface charge and further promote foam stability by increasing electrostatic repulsion between air bubbles. Legumins tend to reduce foamability since they adsorb to the air-water interface slowly and tend to disrupt the interfacial network structure. These findings provide deeper insights in the role of pulse globulins and albumins in air-water interface and foam stabilization. The proposed key parameters will benefit the predictability of the interfacial and foaming behavior of pulse proteins.

Comparative investigation of composition, microstructure and property influences on electrocatalysis of two representative cathodes: BaCo0.4Fe0.4Zr0.1Y0.1O3-δ versus Ba0.5Sr0.5Co0.8Fe0.2O3-δ

BaCo0.4Fe0.4Zr0.1Y0.1O3-δ (BCFZY) and Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) perovskites are two representative high-performance cathode materials for intermediate-temperature solid oxide fuel cells (IT-SOFCs). Here, symmetric cell tests demonstrate that polarization resistance values of BCFZY cathode are only 0.21–0.29 times those of BSCF cathode at 740–660 °C, and 0.21–0.26 times those of BSCF cathode at the oxygen partial pressures of 1.00–0.10 atm. Distribution of relaxation times (DRT) is applied to detect individual electrode processes overlapped in impedance spectra, which finds that the dominant processes of oxygen dissociation, subsequent species transfer and reduction on BCFZY cathode are superior to those of BSCF cathode. By temperature-programmed desorption of oxygen (O2-TPD), thermal expansion coefficient (TEC) measurements, scanning electron micrograph (SEM) and energy dispersive spectra measurements, the strong oxygen combination ability with higher activation energy of oxygen desorption (Ed = 84 kJ/mol), peculiar surface state with evident nano-particle structure, more matchable TEC (19.0 × 10-6 K−1) and excellent interfacial connection with the electrolyte are observed on BCFZY cathode to account for its distinctive catalysis, as compared to BSCF cathode (Ed = 68 kJ/mol, TEC = 24.2 × 10-6 K−1).

Growth Mechanism of Carbon Nanotubes Revealed by in situ Transmission Electron Microscopy.

Elucidating the growth mechanism of carbon nanotubes (CNTs) is critical to obtaining CNTs with desired structures and tailored properties for their practical applications. With atomic resolution imaging, in situ transmission electron microscopy (TEM) has been a key technique to reveal the microstructure and dynamics of CNTs in real time. In this review, recent advances in the development of in situ TEM with different types of environmental reactors will be introduced. The catalytic growth mechanisms of CNTs revealed by in situ TEM under realistic conditions are discussed from fundamental thermodynamics and kinetics to the detailed nucleation, growth, and termination mechanisms, including the state and phase of active catalysts, interfacial connections between catalyst and growing CNTs, and catalyst-related growth kinetics of CNTs. Great progresses have been made on how a CNT nucleates, grows and terminates, focusing on the interface dynamics and kinetic fluctuations. Finally, challenges and future directions for understanding the atomic dynamics under the real growth conditions are proposed. It is expected that breakthroughs in the fundamental growth mechanisms will pave the way to the ultimate goal of designing and controlling the atomic structures of CNTs for their applications in various devices.

Hierarchical Interfacial Construction by Grafting Cellulose Nanocrystals onto Carbon Fiber for Improving the Mechanical Performance of Epoxy Composites.

Carbon fiber-reinforced composites have been widely used in the aerospace industry because of their superior comprehensive performance, including high strength, low density, fatigue resistance, long service life, etc. The interface between the fiber reinforcement and the matrix is one of the key factors that determines the performance of the composites. The construction of covalent bonding connections between the components has proven to be an effective strategy for improving the interfacial bonding strength but always reduces the toughness. In this work, dual silane coupling agents are applied to covalently connect cellulose nanocrystals (CNCs) onto carbon fibers, constructing hierarchical interfacial connections between the fibers and the epoxy matrix and significantly improving the interfacial bonding strength. As a result, the tensile strength of the epoxy composites increased from 519 MPa to nearly 900 MPa, which provides a potential approach for significantly improving the mechanical performance of composites.

Interfacial Modification for High-Efficient Reversible Protonic Ceramic Cell with a Spin-Coated BaZr0.1Ce0.7Y0.2O3-δ Electrolyte Thin Film.

Slurry spin coating is an effective approach for the fabrication of protonic ceramic electrolyte thin films. However, weak adhesion between the electrode and spin-coated electrolyte layers in electrochemical cells due to the low sinterability of the proton-conducting perovskite materials usually lead to a high interfacial resistance and thus a low performance. Herein, we report a method to improve the interfacial connection and boost the performance of protonic ceramic cells based on a BaZr0.1Ce0.7Y0.2O3-δ (BZCY) electrolyte. Ni-BZCY anode functional layer, BZCY electrolyte layer and La0.6Sr0.4Co0.2Fe0.8O3-δ-BZCY cathode functional layer are all fabricated by slurry spin coating. The electrode functional layers and the components of the electrolyte slurry influence the microstructure of the single cell and the kinetics of the electrochemical processes significantly. A peak power density of 2345 mW cm-2 is achieved at 700 °C in the fuel cell mode, and a current density of -3.0 A cm-2 is obtained at an applied voltage of 1.3 V in the electrolysis mode.

The Loss of Interfacial Water-Adsorbate Hydrogen Bond Connectivity Position Surface-Active Hydrogen as a Crucial Intermediate to Enhance Nitrate Reduction Reaction.

The electrochemical nitrate reduction reaction (NO3RR) offers a promising solution for remediating nitrate-polluted wastewater while enabling the sustainable production of ammonia. The control strategy of surface-active hydrogen (*H) is extensively employed to enhance the kinetics of the NO3RR, but atomic understanding lags far behind the experimental observations. Here, we decipher the cation-water-adsorbate interactions in regulating the NO3RR kinetics at the Cu (111) electrode/electrolyte interface using AIMD simulations with a slow-growth approach. We demonstrate that the key oxygen-containing intermediates of the NO3RR (e.g., *NO, *NO2, and *NO3) will stably coordinate with the cations, impeding their integration with the hydrogen bond network and further their hydrogenation by interfacial water molecules due to steric hindrance. The *H can migrate across the interface with a low energy barrier, and its hydrogenation barrier with oxygen-containing species remains unaffected by cations, offering a potent supplement to the hydrogenation process, playing the predominant factor by which the *H facilitates NO3RR reaction kinetic. This study provides valuable insights for understanding the reaction mechanism of NO3RR by fully considering the cation-water-adsorbate interactions, which can aid in the further development of the electrolyte and electrocatalysts for efficient NO3RR.

Interface engineering of La0.6Sr0.4Co0.2Fe0.8O3−δ/Gd0.1Ce0.9O1.95 heterostructure oxygen electrode for solid oxide electrolysis cells with enhanced CO2 electrolysis performance

For CO2 electrolysis in solid oxide electrolysis cells (SOECs), oxygen evolution reaction in the oxygen electrode limits the electrolysis process due to its slower reaction kinetics. Composite oxygen electrodes with good uniformity and interfacial connectivity are expected to promote the charge carriers' transport effectively and thus increase the electrocatalytic performance of the cell. In this work, interface engineering is applied to promote the conventional La0.6Sr0.4Co0.2Fe0.8O3−δ-Gd0.1Ce0.9O1.95 (LSCF-GDC) composite oxygen electrode to form a heterostructure via co-synthesis method. The results prove that LSCF co-synthesized with 40 wt%GDC (LSCF/40GDC) exhibits higher conductivity and faster oxygen exchange kinetics and bulk diffusion processes. The nickel/yttria stabilized zirconia (Ni-YSZ) supported cell with LSCF/40GDC oxygen electrode could approach an impressive CO2 electrolysis current density of 2.6 A·cm−2 at 1.6 V and 800 °C. Meanwhile the cell can operate at 1.5 V and 750 °C with electrolysis current density of 1.3 A·cm−2 for more than 100 h without apparent degradation. This heterostructure enhances the interfacial bonding strength between LSCF and GDC phases, thereby providing a continuous network structure for electron and ion transport. Such an interface engineering via co-synthesis method offers a straightforward and convenient modification for oxygen electrodes, providing an alternative route for advanced materials development of CO2 electrolysis.

An alternative approach in the synthesis of strontium-hydroxyapatite and strontium hydroxyapatite embedded in graphitic carbon nitride nanocomposites for potential tissue engineering applications

Sr-hydroxyapatite has drawn much attention with promising applications in biomedical engineering especially in drug delivery and tissue repair. A novel protocol for the preparation of Strontium hydroxyapatite (Sr-HAP) and Strontium hydroxyapatite encapsulated by graphitic carbon nitride (Sr-HAP@gCN) with high purity and better homogeneity was adopted for potential use in orthopaedic surgeries. The physiological pathway of Strontium and calcium inside humans follow the same trend leading to the mineral deposition of the bone. In the present study, a novel attempt in synthesizing Sr-HAP and Sr-HAP@gCN by the hydrothermal method is proposed for obtaining an ideal biomaterial with potential biocompatibility and pharmacological activity. Phase identification by X-ray diffraction (XRD), Fourier transform Infra-Red spectroscopic analysis (FTIR), Electron & atomic force microscopic studies, Thermogravimetric and Raman spectroscopic analysis was performed on the prepared Sr-HAP and Sr-HAP@gCN to characterize the incorporation efficiency of Strontium. Resazurin microtiter assay and MTT assay were used to evaluate antimicrobial susceptibility and biocompatibility. The typical crystal phase of Sr-HAP and a phase change in Sr-HAP@gCN have been demonstrated with special reference to the interfacial connection between gCN and Sr-HAP through FT-IR studies. Raman spectroscopy revealed the archetypal signature of symmetric and asymmetric PO vibrations pertaining to linearity change with the addition of Strontium. The biological effect of Sr-HAP and Sr-HAP@gCN was quite significant in inducing mineralization when kept immersed in simulated body fluid (SBF) for 21 days. Promising results pertaining to antimicrobial susceptibility and biocompatibility have been proved as an encouraging choice for drug delivery applications and bone filling applications.

Characterization of load-bearing and failure properties of fractured rock masses reinforced by negative pressure grouting

Grouting injection is a vital technique for addressing the challenges of high stress and significant deformation in the surrounding rock during deep mining operations, playing a crucial role in promoting green and low-carbon extraction methodologies. In this study, grouting reinforcement processes were examined by conducting grouting experiments on a fractured rock with varying negative pressures (0-100 kPa), followed by uniaxial compression testing of the grout-reinforced bodies. This investigation explored the diffusion patterns of grout under negative pressure and established a constitutive model of damage-bearing capacity for bodies reinforced by negative pressure grouting. It further studied the enhancement effect of negative pressure on the load-bearing capacity of the reinforced bodies and analyzed the instability mechanism of damage and failure in these bodies. The results indicated that the diffusion of grout under negative pressure is influenced by four types of forces, which alter the extent of grout diffusion within the fractured rock mass. Introducing a damage constitutive model that serially connects pore and framework elements characterizes the damage and failure behavior of grout-reinforced bodies under different negative pressures. As the negative pressure increases, changes in porosity, water-to-cement ratio, and admixture quantity occur in the grout-reinforced specimens, with the strength mean curve showing a trend of first increasing and then decreasing, reaching a threshold at a negative pressure of 60 kPa. With increasing negative pressure, the negative pressure damage variable decreases and then increases, and the stronger the interfacial microelement connections caused by the negative pressure, the greater the bearing capacity, ultimately manifesting in different failure modes.

Strategically engineered multifunctional graphene oxide hybrid nanomaterials for efficient catalytic degradation and emerging contaminants treatment

The use of functional textiles is growing in all fields of science and technology. Surface functionalization is mainly used to impart conventional textiles with new functionalities and improved performances. In the present study, a cobalt ferrite nanoparticle/graphene oxide (CoFe2O4/GO) coated polyethylene terephthalate (PET) fabric with excellent catalytic and antibacterial properties, has been successfully developed. The PET-coated CoFe2O4/GO samples, ranging from 1 % to 5 % wt. were obtained using a simple dip-coating method in CoFeO/GO solution (1 mg/mL), and were investigated through several physiochemical characterization techniques. CoFe2O4/GO and PET fabric have been shown to establish an interfacial connection by Fourier transform infrared spectroscopy (FTIR). X-ray diffraction (XRD) results showed that CoFe2O4/GO coating did not affect the PET crystallinity and that CoFe2O4/GO hybrid was incorporated in the PET samples, which was proved as well by the morphological study through Scanning electron microscopy (SEM). Furthermore, thermogravimetric characterisation (TGA) verified that the coating does not change or impair the quality of the fibre and that the PET@CoFe2O4/GO as made is thermally stable. Tensile strength tests demonstrated that coated fabrics exhibited outstanding mechanical properties in comparison with pristine PET. Moreover, the coated PET@CoFe2O4/GO fabric was used as a model catalytic system for peroxymonosulfate (PMS) activation in the rhodamine B (RhB) degradation reaction. Total Organic Carbon (TOC) measurements showed that TOC removal reached 89.82 % in only 12 min reaction. The results confirmed that the coated fabrics exhibited high catalytic performances, good stability and reusability in consecutive degradation experiments with a degradation rate over 60 % even after 7 degradation cycles; Moreover, it is easily and simply separated from the mixture, by removing the textile sample from the aqueous solution. It is worth mentioning that the PET@CoFe2O4/GO fabrics showed outstanding antibacterial activity against both Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria with an inhibition diameter zone of up to 13 mm for PET@CoFe2O4/GO (5 %). Overall, these findings are of great importance as they permit the development of a novel multifunctional textile fabric, combining anti-bacterial activity, catalytic performance and mechanical properties. The study provides a textile-based catalyst with improved catalytic performance, re-usability in consecutive degradation reactions and easy catalyst separation compared to traditional supports. Thus, a huge potential application in several fields such as medicine, heterogeneous catalysis, and wastewater treatment.

Molecular Dynamics Analysis of Surface-Modified Carbon Nanoparticle Reinforced Epoxy Resin.

Surface-modified carbon nanoparticles (CNPs) as reinforcement materials have attracted significant attention due to their potential for substantially enhancing mechanical properties. However, the development and application of CNP-enhanced polymeric materials are constrained by an incomplete understanding of their reinforcement mechanisms, impeding sustainable progress. In this study, we employed molecular dynamics simulations to investigate the mechanical properties of surface-modified CNP-reinforced epoxy resin composites at the microscopic scale. The simulations focused on the tensile process and the nanopinning effect of CNPs within the epoxy resin matrix. Our results indicate that surface-modified CNPs form stronger interfacial connections with the epoxy resin, leading to enhanced mechanical strength of the composites. Quantitative analysis revealed that these composites exhibit higher tensile strength compared to nonmodified counterparts, with a significant improvement in stability due to the robust noncovalent interactions between CNPs and the epoxy matrix. This study elucidates the reinforcement mechanisms of surface-modified CNPs in polymers, providing valuable insights for further optimization and sustainable development of CNP-reinforced polymeric materials.

Materials, Structure, and Interface of Stretchable Interconnects for Wearable Bioelectronics.

Since wearable technologies for telemedicine have emerged to tackle global health concerns, the demand for well-attested wearable healthcare devices with high user comfort also arises. Skin-wearables for health monitoring require mechanical flexibility and stretchability for not only high compatibility with the skin's dynamic nature but also a robust collection of fine health signals from within. Stretchable electrical interconnects, which determine the device's overall integrity, are one of the fundamental units being understated in wearable bioelectronics. In this review, a broad class of materials and engineering methodologies recently researched and developed are presented, and their respective attributes, limitations, and opportunities in designing stretchable interconnects for wearable bioelectronics are offered. Specifically, the electrical and mechanical characteristics of various materials (metals, polymers, carbons, and their composites) are highlighted, along with their compatibility with diverse geometric configurations. Detailed insights into fabrication techniques that are compatible with soft substrates are also provided. Importantly, successful examples of establishing reliable interfacial connections between soft and rigid elements using novel interconnects are reviewed. Lastly, some perspectives and prospects of remaining research challenges and potential pathways for practical utilization of interconnects in wearables are laid out.

Lignin-polylactic acid biopolymer blends for advanced applications – Effect of impact modifier

In this study, lignin underwent chemical modification via acetylation of hydroxyl groups to enhance its interfacial connection with poly (lactic acid) (PLA). Further enhancement of the blend was attained by adding an impact modifier, Biomax Strong. Incorporating Biomax Strong into PLA-lignin blends resulted in improvements in material characteristics, particularly in impact strength and thermal stability. This blend exhibited a unique set of mechanical properties, characterized by a reduction in tensile modulus as well as an increase in ductility. This will allow a more versatile use of PLA in various applications. The observed improved impact strength highlights the synergistic effect of stress redistribution within the PLA matrix contributing to widespread applications of PLA based composites. This can clearly be observed for the compound containing PLA and 15 wt.% lignin, where the impact strength was approximately 15 kJ/m2. With the addition of 5 wt.% impact modifier, the impact strength increased by 60 %, reaching approximately 25 kJ/m2. This synergy effect reinforces the overall structure, improving the impact toughness behavior. The combination of Biomax Strong and lignin not only address the limitations of PLA but also introduces new opportunities for applications requiring a balance of impact strength, ductility, and thermal stability. These advancements indicate a promising future for composite materials in various applications.

Highly Robust and Self-Adhesive Soft Strain Gauge via Interface Design Engineering.

Highly robust soft strain gauges are rapidly emerging as a promising candidate in the fields of vital signs and machine conditions monitoring. However, it is still a key challenge to achieve high-performance strain sensing in these sensors with mechanical/electrical robustness for long-term usage. The multilayer structural design of sensors enhances sensing performance while the interfacial connection of heterogeneous materials between different layers is weak. Herein, inspired by the efficient perception mechanism of scorpion slit sensilla with tough interface interconnections, the synergy of ultra-high electrical performance and mechanical robustness is successfully achieved via interface design engineering. The developed multilayer soft strain gauge (MSSG) exhibits a strain sensitivity beyond 105, a lower detection limit of 8.3µm, a frequency resolution within 0.1Hz, and cyclic stability over 63000 strain cycles. Also, the tough interface improves the level of heterogeneous integration in the MSSG which allows to endure different stresses. Furthermore, an MSSG-based wireless strain monitoring system is developed that enables applications on different complex dynamic surfaces, including accurate identification of human throat activity and monitoring of rolling bearing conditions.

Enhancing concrete durability and strength: An innovative approach integrating abrasion and cement slurry treatment for recycled coarse aggregates

AbstractThis study introduces a novel approach to enhance the durability and strength of concrete by integrating abrasion and cement slurry treatments on surface‐treated recycled coarse aggregates (STRCA). Initial abrasion treatment removes aged mortar from the recycled coarse aggregate (RCA) surface, while subsequent cement slurry modification provides a fresh surface, reinforcing the bond with the concrete matrix. Through detailed material analyses including x‐ray diffraction, scanning electron microscopy, and energy‐dispersive x‐ray, microstructural changes are evaluated alongside compressive strength, drying shrinkage, electrical resistivity, and chloride ion penetration of STRCA‐based concrete. Results indicate significant improvements in mechanical properties and durability as the treatments eliminate mortar and enhance the interfacial connection with cement paste. Notably, a substantial 29.37% strength enhancement is observed at 25% replacement (STRCA 25), demonstrating treatment efficacy. While a reduction of 11.58% occurs at 100% replacement (STRCA 100), up to 75% replacement shows minimal strength loss, with optimal enhancements at 50% replacement. Additionally, STRCA concrete exhibits lower drying shrinkage (11%–20% reduction) and increased electrical resistivity (28%–36% rise), indicating improved durability at 100% replacement. Enhanced resistance to chloride ion penetration is also evident, with a 22%–28% increase at 100% replacement compared to conventional RCA. Overall, this study highlights the effectiveness of dual treatments for enhancing concrete properties using STRCA.

Stable Hierarchical Porous Heterostructure Ni2P/NC@CoNi2S4 Fabricated via the NiCo-LDH Template Strategy for High-Performance Supercapacitors.

Transition metal phosphide/sulfide (TMP/TMS) heterostructures are attractive supercapacitor electrode materials due to their rapid redox reaction kinetics. However, the limited active sites and weak interfacial interactions result in undesirable electrochemical performance. Herein, based on constructing the NiCo-LDH template on Ni-MOF-derived Ni2P/NC, Ni2P/NC@CoNi2S4 with a porous heterostructure is fabricated by sulfurizing the intermediate and is used for supercapacitors. The exposed Ni sites in the phosphating-obtained Ni2P/NC coordinate with OH- to in situ form an intimate-connected Ni2P/NC@NiCo-LDH, and the CoNi2S4 nanosheets retaining the original cross-linked structure of NiCo-LDH integrate the porous carbon skeleton of Ni2P/NC to yield a hierarchical pore structure with rich electroactive sites. The conducting carbon backbone and the intense electronic interactions at the interface accelerate electron transfer, and the hierarchical pores offer sufficient ion diffusion paths to accelerate redox reactions. These confer Ni2P/NC@CoNi2S4 with a high specific capacitance of 2499 F·g-1 at 1 A·g-1. The NiCo-LDH template producing a tight interfacial connection, significantly enhances the stability of the heterostructure, leading to a 91.89% capacitance retention after 10,000 cycles. Moreover, the fabricated Ni2P/NC@CoNi2S4//NC asymmetric supercapacitor exhibits an excellent energy density of 73.68 Wh kg-1 at a power density of 700 W kg-1, superior to most reported composites of TMPs or TMSs.