Aramid fibers exhibit outstanding properties such as heat resistance, chemical resistance, dimensional stability, durability and elongation. However, their poor dispersibility poses a significant challenge when preparing composites. Consequently, converting aramid fibers into nanofibers is crucial to enhance their dispersibility. In this study, aramid nanofibers with excellent dispersibility were prepared by applying a supercritical fluid drying process. Technora based copolymer para-aramid nanofibers (CANF) were prepared by reacting in a DMSO/KOH basic solution within a short processing time (i.e., less than 3 h), and dried by a supercritical fluid process. We obtained uniformly dispersed CANF without the change in chemical composition. In addition, uniform translucent membrane sheets were prepared by vacuum filtration methods. Their tensile strength was obtained to be 23 MPa with high dimensional stability even at 100 °C without shrinkage, which can provide the possibility of CANF sheets as a separator for lithium-ion batteries.

The rapid advancement of electronic devices has made thermal management a critical issue. In this study, we present phase change material (PCM)-based thermal buffering sheets that provide both heat transfer and heat delay functions. Boron nitride nanosheets (BNNS) with high aspect ratios were obtained by exfoliating bulk h-BN. The conventional exfoliation process had a low yield. In this study, the process was designed to be suitable for large-scale production. To prevent PCM leakage during phase change, paraffin was encapsulated in a silica shell formed by a TEOS-based sol-gel method. This process was conducted within an oil-water emulsion system. BNNS with negatively charged surfaces were added to the emulsion before the complete hydrolysis of TEOS, and the capsules were assembled onto the BNNS surfaces through electrostatic interaction. The resulting hybrid composite of 2D BNNS and 0D capsules was dispersed into an epoxy matrix and processed into sheet-type composites. These materials showed enhanced thermal conductivity and a delayed temperature rise under sudden heat input due to latent heat buffering. The combination of highly thermally conductive BNNS and structurally stable silica-encapsulated PCM suggests a promising direction for thermal buffering sheets that require both heat dissipation and temperature stabilization.

Abstract The selection of suitable polymers is pivotal in influencing the electrical performance and the thermal/electrical stabilities of organic electronics. Here, the superior properties induced by deuteration in polymer/2,8‐difluoro‐5,11‐bis(triethylsilylethynyl)anthradithiophene (diF‐TES ADT) blends are systematically investigated. By employing a combination of experimental and computational analyses, the critical factors underlying charge transport and device stabilities in deuterated polymers (d‐polymers) compared to protonated polymers are elucidated. Deuterated polymers exhibit increased mass due to the substitution of hydrogen with deuterium, reducing the zero‐point vibration energy by 1/√2. This reduction leads to enhanced energetic stabilization and the formation of stronger D─C bonds than H─C bonds. Consequently, deuterated polymers exhibit enhanced thermal properties, along with improved insulating properties, which are intrinsically linked to improved device performance. Additionally, the correlation between the electrical properties and bias stability using deuterated poly(methyl methacrylate) (d‐PMMA) and polystyrene (d‐PS) blends are analyzed. Utilizing complementary neutron & X‐ray reflectivity, and photoexcited charge‐collection spectroscopy (PECCS), phase separation and trap dynamics are delved, providing a comprehensive understanding of these relationships. These findings reveal that d‐polymers significantly enhance the electrical performance and stability of the blends, offering valuable insights for the design of advanced materials in organic electronics.

Aramid fibers exhibit outstanding properties such as heat resistance, chemical resistance, dimensional stability, durability and elongation. However, their poor dispersibility poses a significant challenge when preparing composites. Consequently, converting aramid fibers into nanofibers is crucial to enhance their dispersibility. In this study, aramid nanofibers with excellent dispersibility were prepared by applying a supercritical fluid drying process. Technora based copolymer para-aramid nanofibers (CANF) were prepared by reacting in a DMSO/KOH basic solution within a short processing time (i.e., less than 3 h), and dried by a supercritical fluid process. We obtained uniformly dispersed CANF without the change in chemical composition. In addition, uniform translucent membrane sheets were prepared by vacuum filtration methods. Their tensile strength was obtained to be 23 MPa with high dimensional stability even at 100 °C without shrinkage, which can provide the possibility of CANF sheets as a separator for lithium-ion batteries.

The rapid advancement of electronic devices has made thermal management a critical issue. In this study, we present phase change material (PCM)-based thermal buffering sheets that provide both heat transfer and heat delay functions. Boron nitride nanosheets (BNNS) with high aspect ratios were obtained by exfoliating bulk h-BN. The conventional exfoliation process had a low yield. In this study, the process was designed to be suitable for large-scale production. To prevent PCM leakage during phase change, paraffin was encapsulated in a silica shell formed by a TEOS-based sol-gel method. This process was conducted within an oil-water emulsion system. BNNS with negatively charged surfaces were added to the emulsion before the complete hydrolysis of TEOS, and the capsules were assembled onto the BNNS surfaces through electrostatic interaction. The resulting hybrid composite of 2D BNNS and 0D capsules was dispersed into an epoxy matrix and processed into sheet-type composites. These materials showed enhanced thermal conductivity and a delayed temperature rise under sudden heat input due to latent heat buffering. The combination of highly thermally conductive BNNS and structurally stable silica-encapsulated PCM suggests a promising direction for thermal buffering sheets that require both heat dissipation and temperature stabilization.

Abstract The selection of suitable polymers is pivotal in influencing the electrical performance and the thermal/electrical stabilities of organic electronics. Here, the superior properties induced by deuteration in polymer/2,8‐difluoro‐5,11‐bis(triethylsilylethynyl)anthradithiophene (diF‐TES ADT) blends are systematically investigated. By employing a combination of experimental and computational analyses, the critical factors underlying charge transport and device stabilities in deuterated polymers (d‐polymers) compared to protonated polymers are elucidated. Deuterated polymers exhibit increased mass due to the substitution of hydrogen with deuterium, reducing the zero‐point vibration energy by 1/√2. This reduction leads to enhanced energetic stabilization and the formation of stronger D─C bonds than H─C bonds. Consequently, deuterated polymers exhibit enhanced thermal properties, along with improved insulating properties, which are intrinsically linked to improved device performance. Additionally, the correlation between the electrical properties and bias stability using deuterated poly(methyl methacrylate) (d‐PMMA) and polystyrene (d‐PS) blends are analyzed. Utilizing complementary neutron & X‐ray reflectivity, and photoexcited charge‐collection spectroscopy (PECCS), phase separation and trap dynamics are delved, providing a comprehensive understanding of these relationships. These findings reveal that d‐polymers significantly enhance the electrical performance and stability of the blends, offering valuable insights for the design of advanced materials in organic electronics.

In this study, a one-step process to fabricate "Janus"-structured nanocomposites with iron oxide (Fe₃O₄) nanoparticles (Fe₃O₄ NPs) and polydopamine (PDA) on each side of a graphene oxide (GO) nanosheet using the Langmuir-Schaefer technique has been proposed. The Fe₃O₄ NPs-GO hybrid is used as a high-capacity active material, while PDA is added as a binder due to its unique wet-resistant adhesive property. The transmission electron microscopy image shows a superlattice-like out-of-plane section of the multilayered nanocomposite, which maximizes the density of the composite materials. Grazing-incidence small-angle X-ray scattering results combined with scanning electron microscopy images confirm that the multilayered Janus composite exhibits an in-plane hexagonal array structure of closely packed Fe₃O₄ NPs. This Janus multilayered structure is expected to maximize the amount of active material in a specific volume and reduce volume changes caused by the conversion reaction of Fe₃O₄ NPs. According to the electrochemical results, the Janus multilayer electrode delivers an excellent capacity of ∼903 mAh g^-1 at a current density of 200 mA g^-1 and a reversible capacity of ∼639 mAh g^-1 at 1 A g^-1 up to the 1800th cycle, indicating that this Janus composite can be a promising anode for Li-ion batteries.

Among the various 3D printing methods, direct ink writing (DIW) through extrusion directly affects the microstructure and properties of materials. However, use of nanoparticles at high concentrations is restricted due to difficulties in sufficient dispersion and the deteriorated physical properties of nanocomposites. Thus, although there are many studies on filler alignment with high-viscosity materials with a weight fraction higher than 20 wt %, not much research has been done with low-viscosity nanocomposites with less than 5 phr. Interestingly, the alignment of anisotropic particles improves the physical properties of the nanocomposite at a low concentration of nanoparticles with DIW. The rheological behavior of ink is affected by the alignment of anisotropic sepiolite (SEP) at a low concentration using the embedded 3D printing method, and silicone oil complexed with fumed silica is used as a printing matrix. A significant increase in mechanical properties is expected compared to conventional digital light processing. We clarify the synergistic effect of the SEP alignment in a photocurable nanocomposite material through physical property investigations.

The Cover Feature illustrates of 1D hollow Ti3C2Tx MXene/carbon nanofibers fabricated via electrospinning process. With the tailored surface terminations and an increased specific surface area, the hollow MX/C nanofibers-based Li-ion batteries shows an improved electrochemical performances. More information can be found in the Research Article by D. Seo, M.-R. Kim et al.

Abstract Lithium‐ion batteries (LIBs) are rechargeable batteries that have attracted great interest as next‐generation energy storage devices that will lead future energy technologies because of their various excellent advantages. Two‐dimensional (2D) MXene‐based LIBs have been actively investigated because of their high energy/power density and good performance at high charge/discharge rates. However, three major limitations of 2D MXene electrodes – self‐stacking, low specific surface area, and disturbance of Li + diffusion by surface terminations – have hindered the commercialization of MXene‐based LIBs. Herein, we fabricate 1D hollow Ti 3 C 2 T x MXene/carbon (MX/C) nanofibers via an electrospinning process and use them as anode materials in LIBs. Compared with the pristine 2D MXene (MX) paste electrode and MXene/carbon (MX/C) paste electrode, the hollow MX/C nanofibers electrode exhibits a greater specific surface area, less self‐stacking of flakes, and surface functional groups tailored for LIBs. The LIBs based on the hollow electrode exhibit a higher energy density (306.5 mA h g −1 at 40 mA g −1 ) than those with the MX paste electrode (81.08 mA h g −1 at 40 mA g −1 ) and MX/C paste electrode (196.9 mA h g −1 at 40 mA g −1 ). In addition, the hollow MX/C nanofiber electrode shows a high reversible capacity, proving that it is a promising anode material for LIBs.

Recently, soft electronics have attracted significant attention for various applications such as flexible devices, artificial electronic skins, and wearable devices. For practical applications, the key requirements are an appropriate electrical conductivity and excellent elastic properties. Herein, using the cyano-silver complexes resulting from coordination bonds between the nitrile group of poly(styrene-<i>co</i>-acrylonitrile) (SAN) and Ag ions, a self-healing elastomer demonstrating electrical conductivity is obtained. Because of these coordination complexes, the Ag-SAN elastomer possesses elasticity, compared with pristine SAN. The fracture strain of the Ag-SAN elastomers increased with the amount of added Ag ions, reaching up to 1000%. Additionally, owing to the presence of reversible coordination bonds, the elastomer exhibits self-healing properties at room temperature and electrical conductivity, thereby improving the possibility of its utilization in novel applications wherein elastic materials are generally exposed to external stimuli.