Electromagnetic Interference Shielding of Carbon Nanotube and Carbon Fiber Laminates: Approach for Layup Optimization

ABSTRACT Carbon nanotube (CNT) and carbon fiber hybrid laminates have demonstrated tailorable electromagnetic interference (EMI) attenuation capabilities governed more by laminate architecture than CNT content. In this study, CNT sheets with an areal density of 8 g m ⁻² were incorporated into unidirectional prepreg with IM7 fibers and CYCOM 5250‐4 bismaleimide resin in various layup configurations. EMI shielding effectiveness was measured using the transmission‐line method. Placing fewer CNT layers near the neutral plane yielded higher shielding effectiveness results than placing more CNT layers within a few skin depths of the laminate surface. A mechanism for this unexpected behavior is proposed. Simulations of shielding properties were performed with Ansys HFSS to design laminate layups that optimize EMI shielding performance. The optimized layup achieved nearly 30% greater shielding effectiveness over the unoptimized laminates while using fewer CNT layers. Furthermore, flexural testing indicated minimal impacts on mechanical properties with the addition of CNT layers. This work shows that EMI shielding effectiveness can depend more on intentional layup designs than on the quantity of shielding material.