No abstract

Revolutionary communication technologies including 5G and their correlated microelectronic equipment have generated the new generation of electronic components with a higher power density, which not only would bring electromagnetic waves (EMWs) radiation pollution but also would produce a lot of waste heat problems. In order to satisfy the requirements of advanced electronic components for the multifunctionality, light weight, flexibility, and complex structure, in this work, the polyolefin elastomer (POE)/graphene nanoplatelets (GNPs) nanocomposites with tailorable porous structures were successfully prepared through effectively combining the ultrasonic dispersion strategy with the fused deposition modeling (FDM) 3D printing technology. The results show that the synergistic effect of the constructed GNP network structure and the FDM printed porous structure could effectively enhance the electromagnetic shielding (EMI SE) performance of the 3D printed parts and meet their increasing demands for thermal management. When the content of the incorporated GNPs is 10.93 vol %, the EMI shielding efficiency (SE) value of the printed part could be up to 35 dB, and the value of the thickness-normalized specific SE (SSE/t) under the best printing conditions (50% infill density) could reach up to 244.9 dB•cm 2 /g. In addition, the achieved maximum thermal conductivity is 4.3 W/(m•K), which is 1600% higher than that of the pure POE matrix. The excellent flexibility of the printed pad also ensures its good contact with the electronic device during operation. Finally, the COMSOL simulation results verify the application feasibility of the FDM printed part. This work provides a novel strategy for preparation of customizable and multifunctional porous flexible parts, which is expected to be applied in the field of microelectronics such as communication intelligent devices.

No abstract

High-performance flexible piezoelectric polymer− ceramic composites are in high demand for increasing wearable energy-harvesting applications. In this work, a strategy combining solid-state shear milling (S 3 M) and fused filament fabrication (FFF) 3D-printing technology is proposed for the fabrication of high-performance biomimetic wearable piezoelectric poly-(vinylidene fluoride) (PVDF)/tetraphenylphosphonium chloride (TPPC)/barium titanate (BaTiO 3 ) nanocomposite energy harvesters with a biomimetic fish-scale-like metamaterial. The S 3 M technology could greatly improve the dispersion of BaTiO 3 submicrometer particles and the interfacial compatibility, resulting in better processability and piezoelectric performance of the nanocomposites. Typically, the FFF 3D printed energy harvester incorporating 30 wt % BaTiO 3 showed the highest piezoelectric outputs with an open-circuit voltage of 11.5 V and a short-circuit current of 220 nA. It could hence drive nine green LEDs to work normally. In addition, a 3D-printed biomimetic wearable energy harvester inspired by an environmentally adaptive fish-scale-like metamaterial was further fabricated. The fish-scale-like energy harvester could harvest energy through different deformation motions and successfully recharge a 4.7 μF capacitor by being mounted on a bicycle tire and the tire's rolling. This work not only provides a 3D printing strategy for designing diversified and complex geometric structures but also paves the way for further applications in flexible, wearable, self-powered electromechanical energy harvesters.