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Polymer dielectrics have been widely used in electrical and electronic systems for capacitive energy storage and electrical insulation. However, emerging applications such as electric vehicles and hybrid electric aircraft demand improved polymer dielectrics for operation not only under high electric fields and high temperatures, but also extreme conditions, for example, low pressures at high altitudes, with largely increased likelihood of electrical partial discharges. To meet these stringent requirements of grand electrifications for payload efficiency, polymers with enhanced discharge resistance are highly desired. Here, we present a surface-engineering approach for Kapton® coated with self-assembled two-dimensional montmorillonite nanosheets. By suppressing the magnitude of the high-field partial discharges, this nanocoating endows polymers with improved discharge resistance, with satisfactory discharge endurance life of 200 hours at a high electric field of 46 kV mm −1 while maintaining the surface morphology of the polymer. Moreover, the MMT nanocoating can also improve the thermal stability of Kapton®, with significantly suppressed temperature coefficients for both the dielectric constant and dielectric loss over a wide temperature range from 25 to 205 °C. This work provides a practical method of surface nanocoating to explore high-discharge-resistant polymers for harsh condition electrification. 

The organic insulator–metal interface is the most important junction in flexible electronics. The strong band offset of organic insulators over the Fermi level of electrodes should theoretically impart a sufficient impediment for charge injection known as the Schottky barrier. However, defect formation through Anderson localization due to topological disorder in polymers leads to reduced barriers and hence cumbersome devices. A facile nanocoating comprising hundreds of highly oriented organic/inorganic alternating nanolayers is self‐coassembled on the surface of polymer films to revive the Schottky barrier. Carrier injection over the enhanced barrier is further shunted by anisotropic 2D conduction. This new interface engineering strategy allows a significant elevation of the operating field for organic insulators by 45% and a 7× improvement in discharge efficiency for Kapton at 150 °C. This superior 2D nanocoating thus provides a defect‐tolerant approach for effective reviving of the Schottky barrier, one century after its discovery, broadly applicable for flexible electronics.

 

Nature not only carefully prepares ingenious raw materials but also continuously inspires and guides human beings to create a wide variety of intelligent materials. As the most abundant mineral resource on earth, clay minerals are no longer synonymous with ceramics and cements. Many natural clay minerals can be exfoliated into single‐ or few‐layered nanosheets with exquisite physicochemical properties, which can be reassembled into functional membranes with a macroscopic controllable size and microscopic ordered structure. They are thus used in many fields including chemistry, biology, energy, and environmental science. Strategic design represents one of the key processes to enhance the value of clay minerals and broaden their applications. In this work, the three frequently used approaches of exfoliation are highlighted and the six routes of assembly including casting, dip‐coating, spray coating, vacuum filtration, electrophoretic deposition, and 3D printing are compared. The corresponding principles and advantages are summarized. Representative applications of clay‐based multifunctional membranes in protection, separation, responsiveness, flexible electronics, and energy conversion are presented. The challenges and future perspectives of the clay‐based multifunctional membranes are discussed.

 

In this work, an environmentally friendly and novel oxide‐based mechanoluminescent material, Sr₃Al₂O₆: Eu³⁺, which can serve as the alternative for the widely used but environmentally hazardous transition metal–doped sulfides is reported. This oxide could exhibit highly efficient photoluminescence, but even more efficient mechanoluminescence as embedded into polydimethylsiloxane matrix under mechanical stimulation. The emitting color of the resultant Sr₃Al₂O₆: Eu³⁺/polydimethylsiloxane elastomer composites could be further manipulated by adjusting the synthesis atmosphere of the Sr₃Al₂O₆: Eu³⁺based on its unique self‐reduction characteristic. Moreover, by combining the wavelength selectivity of photoluminescence and dynamic stress response of mechanoluminescence, Sr₃Al₂O₆: Eu³⁺enables the design of two types of intriguing devices. They are a dual‐responsive anticounterfeiting flexible device activated by either photons or mechanics, and a comprehensive stretching/strain sensor capable of sensing both strain level and stretching states. In comparison to the conventional luminescent materials, with a rare combination of efficient photoluminescence, highly sensitive mechanoluminescence, and facile color tunability, Sr₃Al₂O₆: Eu³⁺is much more versatile and ideal for various advanced applications.

 

Hydrogels and polydimethylsiloxane (PDMS) are complementary to each other, since the hydrophobic PDMS provides a more stable and rigid substrate, while the water‐rich hydrogel possesses remarkable hydrophilicity, biocompatibility, and similarity to biological tissues. Herein a transparent and stretchable covalently bonded PDMS‐hydrogel bilayer (PHB) structure is prepared via in situ free radical copolymerization of acrylamide and allylamine‐exfoliated‐ZrP (AA‐e‐ZrP) on a functionalized PDMS surface. The AA‐e‐ZrP serves as cross‐linking nano‐patches in the polymer gel network. The covalently bonded structure is constructed through the addition reaction of vinyl groups of PDMS surface and monomers, obtaining a strong interfacial adhesion between the PDMS and the hydrogel. A mechanical‐responsive wrinkle surface, which exhibs transparency change mechanochromism, is created via introducing a cross‐linked polyvinyl alcohol film atop the PHB structure. A finite element model is implemented to simulate the wrinkle formation process. The implication of the present finding for the interfacial design of the PHB and PDMS‐hydrogel‐PVA trilayer (PHPT) structures is discussed.