Fabrication of PVA-based electromagnetic interference shielding composite film by improving the dispersibility of carbon nanomaterial via m-LDH modification

A good dispersion of carbon (C) nanoparticles is a crucial factor to ensure good electrical conductivity and electromagnetic interference shielding effectiveness (EMI SE) performance of polymer-based composite films. In the present work, water-dispersed monolayer layered double hydroxides (m-LDH) was used to modify the C nanoparticles via an in-situ growth method and applied as the conductive fillers for polyvinyl alcohol (PVA) composite films. The prepared C@m-LDH hybrids displayed good water dispersibility due to the in-situ growth of m-LDH with high dispersibility and small particle size on the surface of C nanoparticles, as well as the synergistic effect of styrene-maleic anhydride copolymer attached to the m-LDH surface. The property testing experiments for the PVA composite films demonstrated that compared with pristine C nanoparticles, as-prepared C@m-LDH hybrids exhibited greatly enhanced the electrical conductivity and higher EMI SE performance. Moreover, PVA/C@m-LDH composite film exhibit remarkably low permeation thresholds, especially PVA/CB@m-LDH composite film, CB@m-LDH content is only 0.4 wt%. In order to further improve the electrical conductivity and EMI SE performance, hybrid fillers of CB@m-LDH/CNT@m-LDH were added in the composite films with different mass ratios. Among, the polymer composite films containing 30 wt% CB@m-LDH/CNT@m-LDH with a mass ratio of 12:1 achieves a high EMI SE value up to 29 dB at a thickness of 0.2 mm, indicating the potential use of these materials for electromagnetic shielding application in the X-band frequency region. The present study paves the way for designing high-performance polymer-based composite film by Cnanoparticles functionalization and altering processing conditions for efficient microwave shielding material.