Polymer blend templated hierarchical porous composites with segregated structure and enhanced electromagnetic interference shielding performance

Abstract Conductive network built by less conductive filler is vital for high‐performance conductive polymer composites. Herein, porous ultrahigh molecular weight polyethylene (UHMWPE)/poly(vinylidene fluoride) (PVDF) blends filled with multi‐walled carbon nanotubes (MWCNT) were fabricated, where poly(lactic acid) (PLA) and polymethyl methacrylate (PMMA) were served as sacrificial template. An interconnecting conductive network is formed based on the UHMWPE segregated structure and PVDF co‐continuous structure in porous UHMWPE/PVDF/MWCNT (UFC) composites. The UFC composites demonstrate a low electrical percolation threshold (0.25 wt%) due to the segregated/co‐continuous structure. Porous UFCs exhibit higher electromagnetic interference shielding effectiveness (EMI SE) than their compact counterparts. The blend‐templated porous structure enhances the EMI SE of composites because a well‐dispersed and densely packed MWCNT network is formed around the polymer particles, facilitating the multiple reflections of electromagnetic waves inside the composites. This effort provides a facile way for preparing high‐performance shielding materials by controlling the hierarchical structure and conductive filler distribution. Highlights Hierarchical porous structure was constructed by blend sacrificial templating method. Carbon fillers are exclusively distributed at blend interface, forming the segregated structure. Porous composites exhibit better shielding performances than their solid counterparts.