Scalable 3D textile with hierarchically functionalized pyramidal units using nanostructured polyamide@carbon/Fe3O4 fibers for tunable microwave absorption

Abstract

Most of the existing flexible microwave absorbing materials (MAMs) are in forms of nonwoven or woven composites. However, the nonwoven ones always show the poor mechanical properties and the woven ones normally involve with the complex fabrication processes and present heavy weight (>1.0 g/cm3), large thickness (>4.0 mm), and impermeability, which greatly hinder their wearable applications. Herein, a scalable 3D textile with hierarchically functionalized pyramidal units using the polyamide@carbon/Fe3O4 fibers (PCF) was successfully fabricated via a simple combined process of melt-spinning and three-dimensional (3D) weaving technologies. The core-sheath PCF can be continuously fabricated with a high production rate of 6000 m/min using pristine polyamide as core and the modified polyamide doped with carbon black and Fe3O4 nanoparticles as sheath. As a result, the as-prepared PCF are easily woven into various 3D textiles with pyramid periodic and impedance matching-lossy-dielectric multilayer structures, simultaneously achieving the impedance gradient and destructive interference. More importantly, changing the size of pyramid structures can tailor the microwave absorption performance. Consequently, the high-density polyamide@carbon/Fe3O4 textile has high-efficiency microwave absorption ability, showing lightweight (0.3 g/cm3), small-thickness (3.2 mm), strong (-47.51 dB), and broadband (5.2 GHz). Besides, the 3D structures endowed the textile with excellent mechanical property, superior flexibility, outstanding breathability and good heat insulation property, which is better than similar MAMs. This work provides a promising strategy for facile and large-scalable production of microwave absorption textiles with high overall performance.