Interfacial Compatibility Research Articles

Construction of “organic–inorganic” hierarchical structure of carbon fibers and the effect on the properties of epoxy composites

AbstractThe demand for epoxy (EP) in semiconductor, aerospace, and other applications is currently on the rise. However, pure epoxy is difficult to meet these requirements, such as low thermal conductivity and poor toughness. Therefore, in this paper, sulfonamides (SAs) and core‐shell silica (SLC‐SiO2) were grafted onto the surface of short carbon fibers (SCF) with sizes of 0.1–6 mm by the chemical grafting method. As a result, the surface activity of SCF was improved and the interfacial properties of the EP composites were enhanced. The interfacial compatibility of SCF grafted with SAs and SLC‐SiO2 in EP is greatly improved, resulting in stronger mechanical interlocking and chemical bonding ability between EP and SCF. The results showed that when the content of SCF@SAs@SLC‐SiO2/EP composites reached 0.3 wt% of SCF@SAs@SLC‐SiO2, the impact and tensile strengths were increased from 12.15 kJ·m−2 and 43.4 MPa to 16.93 kJ·m−2 and 74.97 MPa compared with the pure epoxy, which were improved 39.3% and 72.7%. In addition, the thermal conductivity of SCF@SAs@SLC‐SiO2/EP composites was also improved by 12.5% from 0.205 W·(m·K)−1 to 0.2306 W·(m·K)−1 compared with the pure EP. This is due to improved chemical interactions and mechanical interlocking at the fiber‐epoxy interface. This study provides a new method for the preparation of high‐performance SCF/EP composites.Highlights The amino group of sulfonamides was grafted with short carbon fiber to increase the surface active group of short carbon fiber. Sulfonamides react with carboxyl groups on the surface of core‐shell silica to form an “organic–inorganic” structure. Improve the surface roughness of short carbon fiber, and make it evenly dispersed in epoxy resin, so as to improve the performance of epoxy composite materials.

A Hollow Hemispherical Mixed Matrix Lithium Adsorbent with High Interfacial Interaction for Lithium Recovery from Brine

Mixed matrix lithium adsorbents have attracted much interest for lithium recovery from brine. However, the absence of an interfacial interaction between the inorganic lithium-ion sieves (LISs) and the organic polymer matrix resulted in the poor structural stability and attenuated lithium adsorption efficiency. Here, a novel hollow hemispherical mixed matrix lithium adsorbent (H-LIS) with high interfacial compatibility was constructed based on mussel-bioinspired surface chemistry using a solvent evaporation induced phase transition method. The effects of types of functional modifiers, LIS loading amount, adsorption temperature and pH on their structural stability and lithium adsorption performance were systematically investigated. The optimized H-LIS adsorbent with the LIS loading amount of 50 wt.% possessed the structural merit that the LIS functionally modified by dopamine exposed on both the inner and outer surfaces of the hollow hemispheres. At the best adsorption pH of 12.0, it showed a comparable lithium adsorption capacity of 25.68 mg·g−1 to the powdery LIS within 4 h, favorable adsorption selectivity of Mg/Li and good reusability that could maintain over 90% of lithium adsorption capacity after the LiCl adsorption—0.25 M HCl pickling-DI water cleaning cycling processes for three times. The interfacial interaction mechanism of H-LIS for lithium adsorption was innovatively explored via advanced microcalorimetry technology. It suggested the nature of the Li+ adsorption process was exothermic and dopamine modification could reduce the activation energy for lithium adsorption from 15.68 kJ·mol−1 to 13.83 kJ·mol−1 and trigger a faster response to Li+ by strengthening the Li+-H+ exchange rate, which established the thermodynamic relationship between the structure and Li+ adsorption performance of H-LIS. This work will provide a technical support for the structural regulation of functional materials for lithium extraction from brine.

Sustainable strategy for lignin etherification and its promotion of anti-UV aging PLA biocomposite

Achieving efficient modification of both phenolic (Phe)-OH and aliphatic (Aliph)-OH groups in lignin simultaneously via sustainable method, remained a significant challenge. In this study, a series of highly hydroxyl-substituted alkali lignin phenyl propylene ketone ethers (ALK) were obtained under 50 °C without any by-products via the mild and sustainable hydroxyl-yne click reaction method. Notably, phenolic (Phe)-OH content of lignin decreased from 4.12 mmol g−1 to 0.07 mmol g−1 with a conversion rate of 98 %, while the aliphatic (Aliph)-OH content of lignin decreased from 2.57 mmol g−1 to 0.10 mmol g−1 with a conversion rate of 96 %. Owing to the efficient etherification, ALK showed excellent organic solvent (such as trichloromethane, DCM, THF, and acetone) solubility, which thereby improving the interfacial compatibility between ALK and PLA matrix. 3 wt% ALK obviously enhanced the mechanical properties of ALK/PLA biocomposite films, with the yield strength, breaking strength, and Young’s modulus improving by 114.2 %, 30.7 % and 250.2 %, respectively. Additionally, due to the newly introduced vinyl ether bonds (−C–O–CC–) in ALK by hydroxyl-yne click reaction, only 1 % ALK could endow ALK/PLA biocomposite with excellent UV shielding (100 %), high transmittance (84.3 %) and Anti-UV aging property. The yield strength and Young’s modulus represented an increase of 209 % and 86 %, respectively, even after 3 h of UV-irradiation. This study presents an environmentally friendly lignin functionalization method that unleashes the inherent Anti-UV aging properties of lignin, opening new avenues for the development of high-performance lignin-based composites.

Enhancing insulating properties of glass-fiber reinforced polymers using plasma fluorination-modified boron nitride nanosheets

The insulation failure of glass fiber-reinforced polymers (GFRP) limits their use in high-voltage insulation fields. In this study, boron nitride nanosheets (BNNS) were prepared using ball-milling and further fluorinated via dielectric barrier discharge (DBD) plasma treatment. The GFRP nanocomposites were fabricated using different filler types and doping concentrations. The test results indicated that fluorinated BNNS (F-BNNS) displays good dispersion and interfacial compatibility, enhances the interfacial bonding strength of the “fiber-matrix-filler” ternary system in GFRP, and reduces the internal defects of materials. In addition, the insulating properties of the composites were related to the filler concentration. Adding a trace amount of F-BNNSs increased the flashover and breakdown voltages of the GFRP by up to 28.77% and 21.62%, respectively. The results of molecular dynamics simulations and trap distribution calculations showed that plasma fluorination of BNNS increases the bandgap and deep trap energy level at the interface. The extremely strong charge-binding ability of the deep traps inhibits continuous charge injection and regulates carrier migration, which improves the insulating properties of the composites. The results of this study provide a novel, environmentally friendly, and efficient solution for improving the insulating properties of GFRP.

Construction of ternary hierarchical heterostructures with favorable interfacial compatibility for ultrahigh photocatalytic H2O2 production

Sluggish charge transfer dynamics are still the key issue limiting the development of photocatalysis. In this study, CdS/ZnIn2S4/MIL-53-NH2 ternary hierarchical heterostructures were constructed via a building block approach, where ZnIn2S4 lamellae first grow on MIL-53-NH2 followed by CdS nanoparticle deposition. The favorable interfacial compatibility and ternary heterostructures contribute to rapid and multistep spatial charge transfer, which suppresses charge recombination. Therefore, ultrahigh H2O2 production of 1792 μmol·L−1 was obtained over CdS/Znln2S4/MIL-53-NH2 composites with visible light, pure water and ambient air, which is not only higher than that of each monomer and binary heterostructure but also better than those of most reported references. Notably, the apparent quantum yield reached 4.5 % at 400 nm, and the solar-to-H2O2 conversion efficiency was 0.081 % in pure water and ambient air. Additionally, H2O2 generation over CdS/Znln2S4/MIL-53-NH2 composites involves two-electron O2 reduction with ·O2- as an intermediate. This work may encourage heterostructure design for efficient photocatalytic H2O2 production.

Biomimetic multiscale structure with hierarchically entangled topologies of cellulose-based hydrogel sensors for human-computer interaction

The development of high-performance cellulose-based sensors with superior interfacial compatibility, flexibility, and strength has always been challenging. Drawing inspiration from the intricate multiscale hierarchy found in resilient natural materials, the incorporation of this structure into cellulose-based hydrogels using biomimetic strategies is anticipated to enhance their properties. Therefore, the cellulose/polyacrylamide (PAM) hybrid hydrogels are fabricated using the aqueous AlCl3/ZnCl2 system through an all-green one-pot method at room temperature, achieving efficient dissolution of cellulose at multiple scales and in-situ polymerization of polyacrylamide. The multiscale cellulose/PAM hydrogels achieve good interfacial compatibility, with the reinforcing mechanism being confirmed through a combination of experimental validation and atomic simulations. The findings underscore the key elements that drive the multiscale behavior of hydrogels, encompassing a range of factors such as multiple interfacial interactions, hierarchical molecular entanglements, and microskeleton reinforcement. The hydrogels exhibit satisfactory stretchability (412 %), compressive strength (1.2 MPa), conductivity (1.65 S m−1), and ultralong circulability (> 12,000 cycles), rendering them suitable for various scenarios of human-computer interaction. This work establishes a comprehensive interpretation of the strengthening mechanism in cellulose-based multiscale hierarchical structures, thereby providing novel insights for the advanced design strategies of other promising hierarchical materials.

Surface Coordination of Garnet Fillers Improves the Organic-Inorganic Interfacial Compatibility of Composite Solid Electrolyte.

Composite solid electrolytes (CSEs) have become one of the most promising solid-state electrolytes due to their favorable safety and flexibility. However, the weak interaction between inorganic fillers and polymer matrix leads to poor organic-inorganic interfacial compatibility, which degrades the electrochemical performance of CSEs. Herein, it is demonstrated that Li6.4La3Zr1.4Ta0.6O12 (LLZTO) can be chemically bonded to the polymer matrix by surface coordination of the 1,2-dithiolane group of lipoic acid (LA) with metal atoms on the surface of LLZTO through a combination of experimental investigations and theoretical calculations. The surface coordination not only enhances the interfacial compatibility between LLZTO and the polymer matrix, but also facilitates rapid Li+ transport, which leads to the ionic conductivity of the prepared CSE (P-V-M@LLZTO) as high as 6.1×10-4Scm-1 at 30°C. The excellent interface compatibility ensures a stable cycle of Li/P-V-M@LLZTO/Li symmetrical cell for more than 3500h. As a result, LiFePO4/P-V-M@LLZTO/Li cell delivers the discharge capacity of 161mAhg-1 after 5 cycles with a capacity retention of 81% after 500 cycles at 0.5C under 30°C. This work demonstrates that surface coordination is an effective strategy to solve the inherent interfacial incompatibility problem in CSEs.

Significantly Enhanced Corona Resistance of Epoxy Composite by Incorporation with Functionalized Graphene Oxide

Enhancing the corona resistance of epoxy resin (EP) is crucial for ensuring the reliable operation of electrical equipment and power systems, and the incorporation of inorganic nanofillers into epoxy resin has shown significant potential in achieving this. In this study, functionalized graphene oxide (KHGO) was synthesized via a sol-gel method to enhance the corona resistance of EP with electrochemical impedance spectroscopy (EIS) used to assess the properties of KHGO/EP composites. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) verified the successful grafting of epoxy groups onto the GO surface. The thermal conductivity and stability of the KHGO/EP composite initially increased with KHGO content but declined when the content exceeded 1.2 wt.%. Positron annihilation lifetime spectroscopy (PALS) indicated that KHGO improved interfacial compatibility with EP compared to GO, with agglomeration occurring when KHGO content exceeded a threshold value (1.2 wt.%). EIS analysis revealed that the corona resistance of the KHGO/EP composite was optimal at a filler content of 0.9 wt.%. After corona treatment, the saturation water uptake of the 0.9 wt.% KHGO/EP composite decreased by 15% compared to pure EP with its porosity reduced to just 1/40th of that of pure EP. This study underscores that well-dispersed KHGO/EP composite exhibits excellent corona resistance property suggesting the potential for industrial applications in high-voltage equipment insulation.

Porous TiO2 microspheres containing MgO nanoparticles/epoxy composite with superior thermal conductivity, EMI shielding, and electrical insulation

With the continuous advancement of electronic devices, the amounts of heat as well as electromagnetic (EM) waves generated have increased. Materials with high thermal conductivity and excellent EM interference shielding effectiveness (EMI SE) can be utilized to address this issue. In this work, we synthesized hollow anatase TiO2 microspheres. Through a reaction, MgO nanoparticles were incorporated into the interior of TiO2 microspheres. (H-TiO2/MgO). The heterostructure of the fillers contributed to performance enhancement. TiO2 and MgO particles formed a dual thermal-conduction pathway. H-TiO2/MgO effectively weakened the energy of EM waves upon contact. Additionally, TiO2, MgO, and epoxy all exhibited hydrophilicity. Consequently, the interfacial compatibility between H-TiO2/MgO and epoxy was excellent. They formed strong interfacial interactions by hydrogen bonding. Because of the excellent electrical insulation properties of H-TiO2 and MgO, the composites exhibited superior insulation performance (over 1010 Ω·cm). Our H-TiO2/MgO/Epoxy composites exhibited a maximum thermal conductivity of 7.52 W/m·K, an EMI SE of 64.92 dB, and a tensile strength of 79.10 MPa. Our composites are expected to effectively manage heat and EM waves generated by electronic devices

Functionalization of boron nitride with poly(catechol-polyamine) and bis(γ-triethoxysilylpropyl)tetrasulfide for preparing epoxy nanocomposites with enhanced thermal conductivity

Hexagonal boron nitride (hBN) has garnered significant interest as inorganic thermally conductive material in electronic packaging due to its high-efficiency thermal management capability and electrical insulation properties. However, the relatively inert chemical environment of the BN surface hinders phonon transfer at the interface. Additionally, the high content of inorganic components in the matrix leads to the deterioration of the composite’s mechanical properties. In this research, h-BN surface is modified using poly(catechol-polyamine) (PCPA) and bis (γ-triethoxysi-lylpropyl)tetrasulphide (Si69) (denoted as BN-PCPA-Si69). The noncovalent PCPA modification protects the endothermic properties of BN, Si69 provides covalent bonding between thermally conductive fillers and bisphenol A-type epoxy resin (Ep), and the interfacial compatibility between BN and epoxy resin is improved. The heat conductivity of final BN/Ep composite achieved 0.817 W/(m·K) containing 30 wt% BN. Correspondingly, the heat conductivity of the composite (mBN/Ep) achieved 0.881 W/(m·K) containing 30 wt% BN-PCPA-Si69. Compared to pure epoxy resin (0.200 W/(m·K), the thermal conductivity (TC) of the mBN/Ep composite increased by 364% while maintaining good electrical insulation properties. The proposed BN surface functionalization approach has potential applications in fields such as microelectronic packaging, where materials need to balance high thermal conductivity and electrical insulation.

Gallocyanine-mediated non-covalent functionalization and exfoliation of h-BN for efficient anticorrosion reinforcement of waterborne epoxy coating

Hexagonal boron nitride (h-BN) is commonly used to enhance the anti-corrosion of organic coatings due to its excellent barrier properties, dielectricity and mechanical robustness. However, the bulky h-BN tends to create poor dispersibility and interfacial compatibility problems with the resin matrix, leading to coating cracking and failure. H-BN nanosheets exfoliated by conventional methods only provide passive barrier effect with coatings at the initial stage of corrosion. Herein, we used a mussel-inspired non-covalent functionalization strategy, using the catechol groups and heteroaromatic ring structure of gallocyanine to achieve the functionalization and exfoliation of h-BN through ball milling, and obtained ultra-thin h-BN@G nanosheets. Remarkably, spare gallocyanine can further suppress the erosion, whose inhibition efficiency is 95.48 % at the concentration of 100 mg/L in 1 M HCl within 9 h. Typically, after 105 days of immersion in 3.5 wt% NaCl solution, the low-frequency impedance of h-BN@G/WEP coating is still as high as 1.45 × 109 Ω cm2, which is two orders of magnitude higher than that of the pure coating. The superior long-term anti-corrosion capacity can be ascribed to the triple protection of enhanced shielding property of desirable-exfoliated h-BN, passivation films adsorbed on the metal and coordination bonds formed between gallocyanine and the iron to resist the active corrosion. Our work offers an innovative idea for the functionalization and exfoliation of other lamellar materials, which can be applied to the implementation of long-lasting anti-corrosion coatings.

Mixed matrix membranes (MMMs) fabricated via ultrathin Cu-MOF nanosheets for CO2/N2 separation: Low loading but high performance

Emerging two-dimensional metal-organic frameworks (MOFs) were widely utilized in the fabrication of mixed matrix membranes (MMMs) for CO2/N2 separation, owing to their high specific surface area, high aspect ratio, layered structure, and nanoscale thickness. In the current work, a novel Cu-MOF nanosheet with an approximate thickness of ∼20 nm has been synthesized for the first time and used as nanofillers to fabricate MMMs with Pebax 2533. In the MMMs, these Cu-MOF nanosheets could self-assemble into a unique stacked configuration within the Pebax matrix, facilitating rapid CO2 transport while extending the transport path for N2, thereby enhancing both CO2 permeability and CO2/N2 selectivity of the obtained Pebax-Cu-MOF MMMs. Furthermore, the high aspect ratio of the Cu-MOF nanosheets promotes good interaction with Pebax, thereby improving interfacial compatibility. Under conditions of 2 bar and 35 °C, the CO2 permeability and CO2/N2 selectivity of the Pebax-Cu-MOF 0.2 wt.% MMM was 619.1 Barrer and 23.89, respectively, representing increases of 231.6 % and 112.4 % compared to pure Pebax. The MMMs also demonstrated excellent long-term stability. These novel Cu-MOF nanosheets exhibit significant potential for applications across a wide range of fields.

Robust and Flexible Rubber Composite with High Photothermal Properties Achieved by In Situ ZDMA Assisted Dispersion of Eumelanin and its Hydrophobic Photothermal Application.

Eumelanin, a natural, biocompatible, and biodegradable photothermal agent derived from biomass, has attracted increasingly considerable attention due to its outstanding photothermal conversion efficiency. Unfortunately, its tendency to aggregate in flexible non-polar polymers, owing to its abundant polar groups on the surface, severely restricted the application of eumelanin in photothermal composite field. Herein, a feasible strategy is proposed to disperse eumelanin in non-polar rubber matrix via in situ generation of Zinc dimethacrylate (ZDMA). The graft-polymerization of ZDMA promotes the interfacial compatibility between styrene butadiene rubber (SBR) and eumelanin, achieving a uniform dispersion of eumelanin in SBR. The rubber composite exhibits a considerable tensile strength of 11.4MPa, acceptable elongation at break of 146%, and outstanding photothermal conversion efficiency of up to 75.2% with only 1wt% of eumelanin. Furthermore, based on the easy-processing of SBR matrix, the composite is treated with a sandpaper template technique and sprayed with trimethoxy(1H,1H,2H,2H-perfluorodecyl)silane (PFDTMS) to endow the material with near superhydrophobicity (water contact angle of 147.9°) capacity. Hydrophobicity provides excellent icing resistance, with droplet surfaces extending more than twice as long to freeze. Moreover, this hydrophobic photothermal material exhibits remarkable anti-frosting, de-frosting, and de-icing capabilities.

Development and Characterization of Ethylene‐Vinyl Acetate‐Graphene Nanocomposites

AbstractThe prospective applications of carbon graphene nanoplatelets (GNPs) reinforced ethylene vinyl acetate (EVA) nanocomposites in flexible electronics, energy storage devices, and thermal management systems have attracted a lot of attention. These nanocomposites offer an effective solution for enhancing the electrical conductivity of interfacing materials in electronic systems and addressing issues related to thermal management. GNPs that possess excellent thermal conductivity of 2000–4000 W m−1 K−1 and an electrical conductivity of 107 S m−1 are utilized in this investigation. The homogeneous dispersion of nanofiller and the effective load transfer between components through strong filler/polymer interfacial interactions are essential for the creation of multifunctional polymer nanocomposites. Particularly, their electrical conductivity and dielectric properties are highlighted in this study, with an emphasis on the synthesis and characterization of nanocomposite materials. This work investigates the utilization of graphene nanocomposites in EVA using a melt‐mixing technique assisted by sonication to fabricate multifunctional composites. Incorporating different weight percentages of GNPs (ranging from 0.1 to 0.4 wt.%) within the polymer matrix is carried out. In the present study, the nanocomposites are characterized by scanning electron microscopy investigation and impedance spectrum analysis. The distinctive characteristics of the AC electrical transport in nanocomposites are investigated between 10 Hz and 1 MHz. Excellent interfacial compatibility has been demonstrated by the homogenous distribution of GNPs within the matrix, confirmed by SEM examination. These EVA nanocomposites demonstrate improved electrical conductivity, thereby rendering them very useful for energy storage applications, such as electronic capacitors, wherein supports with a significant dielectric constant and minimal dielectric loss are required.

Sodium Octahydridotriborate as a Solid Electrolyte with Excellent Stability Against Sodium-Metal Anode.

Solid-state sodium metal batteries have been extensively investigated because of their potential to improve safety, cost-effectiveness, and energy density. The development of such batteries urgently required a solid-state electrolyte with fast Na-ion conduction and favorable interfacial compatibility. Herein, the progress on developing the NaB3H8 solid-state electrolytes is reported, which show a liquid-like ionic conductivity of 0.05 S cm-1 at 56°C with an activation energy of 0.35eV after an order-disorder phase transformation, matching or surpassing the best single-anion hydridoborate conductors investigated up to now. The steady polarization voltage and significantly decreased resistance are achieved in the symmetric Na/NaB3H8/Na cell, indicating the great electrochemical stability and favorable interfacial contact with the Na metal of NaB3H8. Furthermore, a Na/NaB3H8/TiS2 battery, the first high-rate (up to 1C) solid-state sodium metal battery using the single-anion hydridoborate electrolyte, is demonstrated, which exhibits superior rate capability (168.2 mAh g-1 at 0.1 C and 141.2 mAh g-1 at 1 C) and long-term cycling stability (70.9% capacity retention at 1 C after 300 cycles) at 30°C. This work may present a new possibility to solve the interfacial limitations and find a new group of solid-state electrolytes for high-performance sodium metal batteries.

Conductivity-enhanced Poly(biphenyl piperidine) anion exchange membranes with organic tubes

Anion exchange membrane fuel cells (AEMFCs) present an economically efficient alternative to proton exchange membrane fuel cells because of the use of non-precious metals. The development of high-performance and durable AEMFCs necessitates the use of highly conductive and robust anion exchange membranes (AEMs). In this study, a novel organic-organic composite AEM was synthesized by preparing poly(arylene piperidinium) polymer through Friedel-Crafts acid condensation and incorporating one-dimensional organic tubes as reinforcing materials. The composite AEM exhibits high conductivity (235 mS cm−1 at 80 °C) due to the chain orientation within the organic tubes and the availability of abundant transport sites. Furthermore, in contrast to the incompatibility of inorganic materials with polymers, the flexible nature of organic tubes enhanced polymer entanglement, significantly boosting the mechanical strength (120 MPa) of the AEM. Crosslinking the polymer backbone with the organic tubes facilitated simultaneous swelling, effectively mitigating interfacial compatibility issues, result in high dimensional stability. The H2–O2 fuel cell employing the developed AEM demonstrated a peak power density of 1018 mW cm−2 at 80 °C. This study provides a comprehensive synthetic strategy for producing stable AEMs with high hydroxide ion conductivity and outstanding mechanical properties tailored for alkaline membrane fuel cell applications.

Curved surface coupled structural battery composites manufactured by resin transfer molding process: Microstructure and multifunctional performance

To bridge industrial production and lab-scale research, this work demonstrates a technology to manufacture curved surface structural battery composites (CSBCs) that can simultaneously achieve electrochemical energy storage and load-bearing. The curved-surface carbon fiber structural anode and cathode are fabricated by coating the active materials on carbon fiber fabric with a vacuum-bag-assisted technique. The resin transfer molding (RTM) process is conducted to manufacture the coupled CSBCs by infusing bi-continuous phase epoxy resin electrolyte and curing at high temperatures. The microstructure of structural electrodes and CSBCs is characterized by scanning electron microscopy (SEM). Due to good interfacial compatibility between high mechanical strength carbon fiber structural electrode and high ionic conductivity solid polymer electrolyte bulk for load support, the fabricated CSBCs demonstrate a high density of 294 mWh kg−1 based on the whole mass of devices, a tensile strength of 257.4 MPa with Young's modulus of 12.9 GPa and a flexural strength of 194.1 MPa with flexural modulus of 11.1 GPa. In situ electrochemical-mechanical tests further confirm the durability of CSBCs under mechanical loads with a multifunctional efficiency of 1.07, suggesting the effectiveness of the introduced manufacturing techniques for coupled structural battery composites.

Isocyanurate‐Derivative Enables Highly Compatible Poly‐Dioxane Electrolyte for Dendrite‐Free Li Metal Batteries

AbstractThe Li+ transport kinetics and electrochemical stability of advanced solid‐state Li metal batteries (SLMBs) are seriously limited by the actual electrolyte compositions. Here, a novel polyether‐based electrolyte (PTGDOX) is presented through in situ co‐polymerization by integrating 1,3‐dioxane with a multifunctional 1,3,5‐triglycidyl isocyanurate additive. The isocyanurate group in PTGDOX not only provides abundant coordinating sites for Li+ transfer and restricts the movement of anions, but also prompts a beneficial inorganic‐rich solid electrolyte interface on the Li electrode. As a result, PTGDOX exhibits a remarkably increased ionic conductivity of 0.48 mS cm−1 at 30 °C and a reasonable Li‐ion transference number of 0.68, enabling the Li||Li symmetric cells to stably cycle for over 2000 h at 1 mAh cm−2. Meanwhile, the assembled Li||LiFePO4 exhibit a 97.4% capacity retention after 700 cycles at 3 C with excellent thermal stability. Moreover, PTGDOX also demonstrates excellent interfacial compatibility with high‐voltage LiNi0.8Co0.1Mn0.1O2 cathode. As such, this work provides a facile and accessible strategy for designing interface‐stable polymer electrolytes and achieving practical dendrite‐free SLMBs.

Engineering a superamphiphilic surface for enhanced interfacial bonding in metal-polymer hybrid structure

Insufficient wetting of polymer due to its poor compatibility with metals leads to non-intimate interfacial mutual contact during the thermal-direct bonding process, thus hindering the establishment of effective mechanical interlocking and substantial chemical bonding at the interface, resulting in deficient performance of metal-polymer hybrid structures. To achieve high-quality bonding between non-polar ultra-high molecular weight polyethylene (UHMWPE) and Ti6Al4V titanium alloy (TC4) for the application of artificial joint prostheses, this study innovatively engineered a superamphiphilic (simultaneously superhydrophilic and superlipophilic) TC4 surface, which was achieved through a morphology-chemistry dual regulation strategy. This pretreatment strategy aimed at improving the interfacial compatibility between in-situ oxidized UHMWPE and TC4 and ensuring intimate contact between these two materials during thermal-direct bonding, thus facilitating chemical reactions and mechanical interlocking at the interface. Defect-free and ultra-high-performance TC4-UHMWPE hybrid joints were successfully obtained via friction spot joining (FSpJ) with the lap shear strength reaching 18.05 MPa (higher than all those similar hybrid joints reported in existing literature) and the fracture was confined to the UHMWPE matrix, effectively avoiding interfacial failure. The formation of chemical bonds in the form of COTi at TC4/UHMWPE interface was solidly confirmed based on X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) analyses. This research presents a compelling strategy for improving interfacial compatibility between polymer and metal for thermal-direct bonding, to overcome the general difficulties in achieving effective interfacial bonding between these two categories of materials with significantly different physiochemical properties.

Biodegradable composites from poly(butylene adipate‐co‐terephthalate) with soybean protein isolate: Preparation, characterization, and performances

AbstractSoy protein isolate (SPI), a widely available and inexpensive natural polymer, can be used as a filler to reduce the cost of poly(butylene adipate‐co‐terephthalate) (PBAT) materials. To improve the compatibility between SPI and PBAT, a series of polycaprolactone‐based polyurethane prepolymers (PCLPUs) with different soft segment molecular weights were synthesized and used as compatibilizers to prepare SPI/PBAT composites. At the same time, the effect of PCLPU soft segment molecular weight on the properties of SPI/PBAT composites was studied. Structural, morphological, and property analyses were carried out on the composite materials; the results showed that PCLPU was an effective compatibilizer for SPI/PBAT composite materials. The –NCO group at its end forms a urethane bond with the hydroxyl group in SPI and PBAT. At the same time, the soft segment of PCLPU is physically crosslinked with PBAT to produce a dual physical and chemical effect. The lower the soft segment molecular weight of PCLPU added, the better the performance of the SPI/PBAT composite materials. This is observed because PCLPU with a lower soft segment molecular weight contains more –NCO functional groups, which can better achieve compatibilization between SPI and PBAT through chemical crosslinking. The addition of 5% PCLPU‐500 content to the SPI/PBAT composite material increased its tensile elongation, impact strength, and tensile strength by 867%, 264%, and 150%, respectively, compared with those of the SPI/PBAT composite material without a compatibilizer, achieving toughening and strengthening with good processability and biodegradability. This work provides a simple, effective solution for preparing high‐performance, green, and low‐cost biodegradable composite materials.Highlights PBAT composites were prepared using soy protein isolate (SPI) as filler. Different types of PCLPU exist as a reactive compatibilizer for PBAT and SPI. Polycaprolactone‐based polyurethane prepolymer significantly improves the interfacial compatibility of PBAT composites. SPI/PBAT film has good degradability and is a rich source of nitrogen.