A facile approach to constructing efficiently segregated conductive networks in poly(lactic acid)/silver nanocomposites via silver plating on microfibers for electromagnetic interference shielding

Here, a facile approach to constructing efficiently segregated conductive networks in the poly(lactic acid)/silver (PLA/Ag) nanocomposites were developed by coating Ag particles on PLA microfibers and then compression molding. The electrical conductivity and electromagnetic interference shielding effectiveness (EMI SE) of the nanocomposites were obviously enhanced by these efficiently conductive networks because of the well Ag coating layers on PLA microfibers. Furthermore, the electrical conductivity and the EMI SE of the nanocomposites increased with increasing the coating amount of Ag particles, which can be easily tuned by controlling the coating time. It was found that the chain-structured PLA/Ag nanocomposites with coating time of 7 min with 5.89 vol% Ag particles possessed the remarkable electrical conductivity of 254 S/m and outstanding EMI SE of 50 dB at 8.2-12.4 Hz when the testing samples with the thickness of 1.5 mm, which far surpassed the targeted value of 20 dB for commercial applications. The excellent EMI shielding properties of the nanocomposites were ascribed to the unique segregated chain-structures, which provide enormous interfaces to reflect, scatter and adsorb the electromagnetic waves many times. The PLA/Ag nanocomposites with segregated networks were also found to be an absorption dominated EMI shielding mechanism.