Copper Electroplated TPMS Polymer Lattices for Lightweight Absorption Dominant Electromagnetic Interference Shielding

ABSTRACT

Triply periodic minimal surface (TPMS) lattice architectures are promising for lightweight electromagnetic interference (EMI) shielding due to their high surface area, interconnected geometry, and tunable relative density. In this study, Schoen‐Gyroid, Schwarz‐Diamond, and Neovius lattices with relative densities of 25%, 30%, and 35% were fabricated using Digital Light Processing (DLP). The samples were dip‐coated with graphene ink and then copper electroplated. Electrical measurements confirmed conductive pathways after dip coating, with up to an 86% reduction in resistance when increasing the dip count from 2 to 3. Copper electroplating further reduced resistance by 90%–98%, yielding values as low as 12.8 Ω. Scanning electron microscopy (SEM) revealed nonuniformities in copper deposition. Gyroid and Diamond lattices showed better internal copper penetration compared to Neovius lattices, attributed to smaller pores and residual resin blockage. These differences were reflected in EMI performance across the X‐band. Electroplated Diamond achieved the highest total shielding effectiveness. SE _T values, averaging 48.72 dB (peak 50.36 dB). The absorption‐loss term exceeded the reflection‐loss term, while impedance matching and attenuation depended on topology and density. Increasing relative density enhanced SE _T across all topologies, with improvement dependent on topology, indicating that geometry and coating quality are as critical as material volume.