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Polymer dielectrics with high breakdown strength (Eb) and high efficiency are urgently demanded in advanced electrical and electronic systems, yet their energy density (Ue) is limited due to low dielectric constant and high loss at elevated temperatures. Conventional inorganic fillers with diameters from nano to micrometers can only increase er at the cost of compromised Eb and Ue due to their poor compatibility with polymer matrix. Herein, hydroxyapa-tite (HAP) sub-nanowires with a diameter of "0.9 nm are incorporated in polyetherimide (PEI) matrix to form HAP/PEI sub-nanocomposites. er and Eb of the composites are concomitantly enhanced with only 0.5 wt.% of HAP sub-nanowires, leading to high Ue of 5.14 (@150 °C) and 3.1 J cm-3 (@200 °C] with efficiency of 90% and high-temperature stability up to 3 x 105 chargedischarge cycles at 200 °C. Microstructural analysis and molecular dynamics simulations indicate that the sub-nanowires with comparable diameter as polymer chains induce enormous interfacial area, substantially increase mobility of polymer chains and form dense traps for charge carriers. This work extends the current research scope of polymer-inorganics composite dielectrics to the sub-nano-level incorporation and provides a novel strategy for fabricating high performance polymer dielectrics at elevated temperatures [ABSTRACT FROM AUTHOR]

Photoelectric sensors based on charge‐coupled device (CCD) and complementary‐metal‐oxide‐semiconductor (CMOS) used to be planar image sensors due to the rigidity of the base materials. Moreover, they are limited to a narrow reaction wavelength range. Here, a conformal broad‐spectra laser sensor based on a flexible metal‐ferroelectric‐metal photocapacitor is promoted. The photocapacitance signal is attributed to the photothermal effect of copper (Cu) electrode and gold nanoparticles (Au NP), and the temperature‐dependent property of the dielectric constant of poly(vinylidene fluoride‐trifluoroethylene) (PVDF‐TrFE). Cu/PVDF‐TrFE/Cu and Cu/Au NP@PVDF‐TrFE/Cu flexible photocapacitors have a reliable photocapacitive response from −60 to 60 °C. Meanwhile, both photocapacitors respond from 265 to 980 nm due to the absorption of light by the composite structure, which can be used for broad‐spectra photodetection. The addition of a small amount of Au NP (0.05 vol%) effectively improves the photoresponsiveness of the device. Real‐time photodetection is realized on a hemispherical surface, and these photocapacitors with conformal characteristics are expected to gain application in an omnidirectional broad‐spectra laser alarming system. [ABSTRACT FROM AUTHOR]

Sub‐nanowires (SNWs) exhibit great potential applications in nanocomposites owing to their high specific surface area, high flexibility, and similarity to polymer chains in dimension, which are a good entry point to bridge inorganic materials and polymer materials. Herein, we synthesized hydroxyapatite sub‐nanowires (HAP SNWs) and engineered hydroxyapatite sub‐nanowires/polyimide (HSP) gels and films by simple mixing of HAP SNWs and polyimide (PI). Benefiting from the interactions between HAP SNWs and PI, these nanocomposites were a continuous hybrid network. As the increase of HAP SNWs contents, the viscosity and modulus of HSP gels were greatly improved by one or two orders of magnitude compared with PI gel. HSP films not only maintained high transparency but also gained high haze, as well as exhibited enhanced Young's modulus. Thus, both HSP gels and films developed in this work are promising for various applications in coatings and high‐performance films. [ABSTRACT FROM AUTHOR]

Sub‐nanowires (SNWs) exhibit great potential applications in nanocomposites owing to their high specific surface area, high flexibility, and similarity to polymer chains in dimension, which are a good entry point to bridge inorganic materials and polymer materials. Herein, we synthesized hydroxyapatite sub‐nanowires (HAP SNWs) and engineered hydroxyapatite sub‐nanowires/polyimide (HSP) gels and films by simple mixing of HAP SNWs and polyimide (PI). Benefiting from the interactions between HAP SNWs and PI, these nanocomposites were a continuous hybrid network. As the increase of HAP SNWs contents, the viscosity and modulus of HSP gels were greatly improved by one or two orders of magnitude compared with PI gel. HSP films not only maintained high transparency but also gained high haze, as well as exhibited enhanced Young's modulus. Thus, both HSP gels and films developed in this work are promising for various applications in coatings and high‐performance films. [ABSTRACT FROM AUTHOR]

Designing metastable refractory high entropy alloys (RHEAs) with transformation induced plasticity (TRIP) effects is an effective approach for solving the low ductility of RHEAs. However, the traditional martensitic transformations (MTs) in RHEAs generally result in limited ductility improvement. In the present work, we designed a metastable RHEA Zr2Hf4Nb0.5Ta (Nb7Ta13) with severe lattice distortion, and two MTs, BCC-to-FCC/α″, were found in Nb7Ta13. During tension deformation, BCC-to-FCC/α″ MTs appeared after yielding, causing the TRIP effect; after the MTs are completed, the FCC martensite showed excellent deformability and effectively promoted the following deformation of Nb7Ta13. Finally, Nb7Ta13 RHEAs show a remarkable ductility (∼60%). By analyzing the variation of interplanar spacing and interatomic spacing during DIMTs, we believed that the FCC martensite is generated by relaxing the lattice distortion. [ABSTRACT FROM AUTHOR]