Drawing advanced electromagnetic functional composites with ultra-low filler loading

Abstract The powdery electromagnetic functional materials severely suffer from the intricate post-compositing/coating process and high weight loading in the ultimate production, which desires a significant revolution of the manufacture technology. Herein, a facile and scalable drawing method is developed for manufacturing a series of flexible, repairable, and high-performance electromagnetic functional coatings with merely ultra-low filler contents. The holography and simulation demonstrate that the drawing process can simultaneously enhance the structural anisotropy and confine the distribution of the filler, thereby significantly reducing the filler content. For instance, the pencil drawing with high dielectric constant holds a record-low graphite content of 4.7 wt%, which sharply reduces by 89.6% compared to traditional polymer/graphite composite. Other six kinds of materials with different dimensions are further employed to prove the universality of the unique drawing method. All these drawings acquire the first-rate electromagnetic stealth and interference shielding performance within a wide effective operating bandwidth of 12 GHz with slight filler weight fractions. Eventually, the as-drawn composites with excellent flexibility and repairability can be easily coated on the equipment without any post-processing. The above achievements endow the drawing method with broad application prospects, such as wearable electromagnetic functional textiles and renewable devices.