Interfacial metallization in segregated poly (lactic acid)/poly (e-caprolactone)/multi-walled carbon nanotubes composites for enhancing electromagnetic interference shielding

Segregated structure was one of the effective approaches to improve electromagnetic interference (EMI) shielding performance of conductive polymer composites. Herein, highly conductive interfaces were constructed by coating silver nanoparticles on the surface of poly (lactic acid) (PLLA) particles in the conventional segregated (CS) PLLA/poly(epsilon-caprolactone)/multi-walled carbon nanotubes (PLLA/PCLNT) composites to form the interface-metallized segregated (IMS) composites. Expectedly, the EMI SE of IMS composites were superior to that of the CS composites with the same MWCNTs loadings. Specifically, the IMS composites with only 0.44 vol% silver achieved an excellent EMI SE of 43.3 dB which was 35% higher than the CS composites (32.1 dB). Furthermore, the EMI SE value of the IMS composites decreased drastically after destroying the segregated structure. Therefore, the EMI SE of the IMS composites was related to both segregated structure and highly conductive interfaces, which could enhance multiple scattering, interfacial polarization and electron hopping at the interfaces.