Digital light processing printed resin based conductive composites with CF @Ag and HGMs @Ag as fillers for metamaterial absorbers

Abstract An integrated fabrication process based on multi‐material Digital Light Processing (DLP) technique for metamaterial absorbers (MMAs) is proposed. Considering the requirements of the DLP process for the rheological properties and photocuring properties of the slurry, a photopolymer resin slurry was developed using silver‐plated carbon fiber (CF@Ag) and silver‐plated hollow glass microspheres (HGMs@Ag) as conductive fillers. To meet the conductivity requirements of resistive films in MMAs, the study systematically investigated the influence of material parameters and DLP process parameters on the conductivity and precision of the fabricated patterns. Optimized DLP parameters for isotropic photocurable conductive composites with high conductivity and low percolation thresholds were obtained. Additionally, a MMAs was designed to achieve effective absorption in the wavelength range of 7 to 28 GHz. The absorber utilized a resistive film with a thickness of 30 μm and an average surface resistivity of 23 ohm/sq., prepared using a photocurable resin filled with a total mass fraction of 35 wt% CF@Ag and HGMs@Ag in a 2:1 mass ratio. This work shows that it is feasible to fabricate resistive film patterns with prescribed surface resistivity and geometric shapes through DLP printing directly without sintering, providing a promising process for the integrated manufacturing of high‐performance MMAs. Highlights Developed a conductive slurry using the synergy between CF@Ag and HGMs@Ag. Proposed the preparation process of resistance controllable resistive film. The first demonstration of manufacturing resistive film‐type MMAs via DLP.