Aijuan Gu

High-yield full-color carbon quantum dots were synthesized using p -phenylenediamine and suitable anhydrides as raw materials under mild hydrothermal conditions, and they showed promising applications in the field of LED devices.

We synthesized polyurethane elastomers with dual dynamic non‐covalent bonds and self‐assembled polyphenylene ether (PPO) fiber‐like structures. The findings reveal that the increased PPO chains can assemble into fiber‐like structures, which can intertwine densely owing to π‐π interactions between the rigid benzene rings. The resultant elastomers possess outstanding mechanical properties including high tensile strength of 19–62 MPa, elongation at break of 248%–1186% and toughness up to 80–113 MJ/m ³ . Moreover, the elastomers display high glass transition temperature (T _g ) of ~95°C. The self‐assembled PPO chains can contribute to the good mechanical stability of the elastomers even at 100°C. The combined effects of dynamic hydrogen bonds and π‐π interactions endow the elastomers with excellent self‐healing and reprocessing abilities. The self‐healing efficiency of tensile strength for the elastomers can reach up to 58%–153% after heating at 140°C for 2 h, and the tensile strength of the remolded elastomers can recover up to 31%–90% of the original values. Owing to the significant phase‐separated structures, the elastomers have excellent shape memory properties. The calculated shape fixation and recovery rates of the elastomers are 78%–81% and 75%–98%, respectively. The flexible sensors based on the elastomers can be used as motion wearable sensors and thermally controlled switches.

Flexible conductive supramolecular polyurethane elastomer composite with high strength was fabricated via the in situ formation of silver nanoparticles (AgNPs) in the surface layer of supramolecular polyurethane elastomer (SPUE) when soaked in silver salt solution. The as‐prepared SPUE/AgNPs composites possessed high tensile strengths of 63–76 MPa, elongations at break of 783%–879%, toughnesses of 230–374 MJ m ⁻³ , and Young's moduli of 7.9–14 MPa. Owing to the compact AgNP layer, SPUE/AgNPs composites had high electrical conductivities of 0.3–3.7 S cm ⁻¹ . When SPUE/AgNPs composites were stretched to a strain of 0.5%, they could show short response time (80–82 ms) and recovery time (140–180 ms). SPUE/AgNPs composites could display stable relative resistance change (Δ R / R ₀ ) values and high strain sensitivities over a wide range of tensile strains (0.05%–200%). Due to the abundant hydrogen bonds, the damaged SPUE/AgNPs composite could be healed under heat treatment condition, and the healed composite could show stable Δ R / R ₀ similar to that of the fresh SPUE/AgNPs composite. Additionally, SPUE/AgNPs composites had good shape memory performances and solvent‐resistances. The as‐prepared SPUE/AgNPs composites could be used as flexible strain sensors and control switches.

Miniaturization and lightweight of power systems urgently ask for polymer dielectrics with high discharged energy density at 150°C. Herein, a molecular design strategy is built to prepare new crosslinkable polyetherimide films (PEIDx, x is the molar ratio of dianhydride to amines) through simultaneously improving the polarization degree and reducing the residual polarization. Thermal, mechanical, and dielectric properties of PEIDx improve as x increases. PEID0.92 shows the best integrated performances, especially its discharged energy density (5.46 J cm⁻³, at 10 Hz and 454 MV m⁻¹) is higher than those of reported polymer dielectrics with discharged energy storage at 150°C, and its charge–discharge efficiency is 80.14%. The outstanding energy storage performance of PEID0.92 is attributed to its unique molecular structure. Specifically, the use of nonplanar and low‐alkaline aliphatic cyclic diamine effectively improves the polarization degree of macromolecules; while the crosslinking of alkynyl groups limits the macromolecular movement, thus ensuring high heat resistance and low residual polarization.

Developing photothermal anti/deicing fluor‐free composite coatings with high wear resistance and liquid puncture resistance is an interesting challenge. Herein, a new biomass benzoxazine monomer (C‐d) was synthesized, which was then sprayed on a glass slide, followed by spraying hyperbranched polysiloxane (HSi), polydopamine‐coated micro AlN (P@mAlN), and polydopamine‐coated nano AlN (P@nAlN), successively, to develop a new type of photothermal anti/deicing four‐layer fluor‐free composite coatings with high wear resistance and liquid puncture resistance (C‐d/yHSi/0.4P@2bAlN, y is the mass ratio of HSi to C‐d). Three‐layer composite coatings (C‐d/0.4P@zbAlN, z is the mass ratio of P@mAlN to P@nAlN) and two‐layer composite coatings (C‐d/xP@mAlN, x is the mass ratio of P@mAlN to C‐d) were also prepared to study the influence of compositions on comprehensive properties of coatings. The results show that C‐d/0.4P@zbAlN has significantly longer icing delay time (IDT) than C‐d and C‐d/xP@mAlN coatings but still shows poor wear resistance and liquid puncture resistance. Interestingly, C‐d/yHSi/0.4P@2bAlN coatings have good superhydrophobicity; as y increases, both IDT and wear resistance increase significantly. When y = 0.5, the obtained C‐d/0.5HSi/0.4P@2bAlN coating has the best integrated performance, including high anti‐deicing property (IDT = 627 s), high wear resistance, and liquid puncture resistance as well as good photothermal deicing performance, the ice melts in 343 s under the irradiation with 808 nm infrared light, overcoming the bottleneck of poor wear resistance and liquid puncture resistance of photothermal anti/deicing coatings. Besides, C‐d/0.5HSi/0.4P@2bAlN coating can effectively prevent the adhesion of pollutants and remain superhydrophobicity after soaked in different solutions (pH = 1–10).Highlights: A new biomass benzoxazine with good flexibility was synthesized. Photo‐thermal anti/deicing coatings with micro/nanostructured surfaces are built. The fluor‐free coatings have excellent wear resistance and chemical resistance. The mechanism behind was elucidated.

We designed three‐dimensional (3D) structures through a combination of glass fiber cloth and in situ formation of nano polyphenylene oxide (PPE) fibers during the fabrication process of thermosetting cyanate ester/bismaleimide composites and developed a self‐stitching technique based on PPE fiber and interpenetrating polymer networks (IPNs) for aiding the crack self‐healing. The building of 3D structure effectively improves the interface interaction between fiber and matrix and suppresses the crack propagation process in composite, leading to significant enhancement in the mechanical properties. When PPE content is 20%, the interlaminar shear strength, flexural strength, impact strength, and tensile strength of the resulting composite are 98%, 74%, 95%, and 101% higher than those of the composite without PPE. The resulting composites possess excellent thermomechanical and lower dielectric properties. Because IPNs within composites can create interspaces and easily deform above glass‐transition temperature, PPE components may penetrate through the interspaces under thermal expansion force, and the contraction stresses of polymers generate strong locking effects in composite after cooling to room temperature, then the crack surfaces of composites can be stitched by PPE fibers, significantly recovering the mechanical properties. The healing efficiency of the composite with 30% PPE after impact and then heating at approximately 280°C can reach 96%.Highlights: 3D structures were constructed during the fabrication process of glass‐fiber‐reinforced thermosetting cyanate ester/bismaleimide composite. A self‐stitching technique was developed for aiding the crack self‐healing of composite. 3D structures significantly improved the interface interaction between fiber and matrix in laminated composite. The mechanical properties of the resulting composite could be significantly improved by 3D structures. The healing efficiency of the healed composite could reach 96%.