3D printed flexible composites based on carbon fiber-led interfacial modification strategy for enhanced microwave absorption

With the rapid popularization of the new generation of wearable flexible electronic products, to enhance the comfort and curved surface fit of the device, while reducing the impact of electromagnetic waves (EMW) emitted from each electronic component on the normal operation of the device, the design of high-performance flexible wave-absorbing composite materials is the key to solve the problem. In this paper, a carbon-fiber-dominated interface modification strategy is proposed based on the in-situ growth of ZIF-CoNi on the surface of carbon fiber as a carrier, and the generation of carbon nanotube arrays on the surface of the carbon fiber (CF) through high-temperature pyrolysis and metal atom-assisted catalytic generation to build up rich heterogeneous interfaces, which induces the generation of interfacial polarization and enhances the attenuation of electromagnetic waves. Melt extrusion was used to make the modified carbon fibers oriented inside the thermoplastic polyurethane (TPU) matrix, and the charge density and volume loss of the oriented and random distribution of carbon fibers in TPU were analyzed based on Comsol simulations. The effective absorption bandwidth of the CF/CoNi@C/TPU thermoplastic composite obtained by the 3D printing technique is 4.81 GHz at 2.14 mm thickness. It realizes the combination of microscopic interface modification design and modern processing engineering of 3d printing, which provides a new idea for the research and development of flexible wave-absorbing composites, and helps to promote the development of the new generation of wearable flexible electronic packaging field in the direction of multi-functional and high-performance.