Construction of lightweight, high-energy absorption 3D-printed scaffold for electromagnetic interference shielding with low reflection

Abstract

The pursuit of advanced electromagnetic interference (EMI) shielding materials, featuring lightweight, programmable structures, low reflection, and essential mechanical properties, presents both promise and challenge. In this study, a scaffold based on triply periodic minimal surface (TPMS) with 70 % porosity was designed using 3D printing technology, showcasing enhanced compressive strength and impressive energy absorption capacity. Building upon this scaffold, the monolithic layered dipping method served as an innovative strategy to easily regulate gradient distribution of carbon nanotube (CNT) on 3D-printed scaffold and ensured their integrity. Moreover, the gradient conductive 3D-printed scaffold, with a rational CNT distribution, features a dramatically reduced reflection power coefficient of 0.13, achieving an EMI shielding effectiveness (SE) up to 35.9 dB, indicating that 99.99 % of EM waves are blocked upon penetration. Finite element analysis (FEA) justifies that the 3D-printed scaffold with increased gradient CNT content was more effective in absorbing EM waves, highlighting its remarkable design flexibility and practical feasibility of gradient conductive structure. Furthermore, we analyze the EM waves attenuation mechanism of gradient conductive 3D-printed scaffold, facilitated by introduces multiple loss mechanisms, which effectively establishing an "absorption-reflection-reabsorption" process for dissipating EM waves. This work is expected to open new avenues in the field of FDM 3D printing technology in the fabrication of low reflection EMI composites.