Contact/non-contact control of electromagnetic shielding performances of flexible graphite nanoplatelet/carbonyl iron-polylactic acid/carbonyl iron shape memory composite film

To cope with the complex electromagnetic interference and electromagnetic pollution environment, it is necessary to develop the electromagnetic interference shielding products with adjustable shielding efficiency. One of the solutions is to modulate the shielding efficiency by changing a shape of the products. In this work, the polylactic acid-graphite nanoplatelets Janus films with both high and modulated shielding efficiency were prepared by hot pressing method. The shape-memory organic polymer Polylactic Acid (PLA) was used as the base material, whose morphology can be adjusted by changing the ambient temperature. The highly conductive Graphite Nanoplatelets (GNPs) was used as efficient electromagnetic shielding layer. And, a small amount of carbonyl iron particles (CIP) was added into the Janus films to enhance the conductivity of GNPs layer, while realize the pre-deformation state of PLA layer under the non-contact magnetic force. As the GNPs layer thickness increased, the maximum electromagnetic shielding performance of the Janus film reached around 68 dB in the frequency range of 8–26.5 GHz. The surface temperature of the Janus film can be regulated by applying contact current and non-contact light irradiation, to realize the deformation of the Janus film. The electromagnetic shielding performance of Janus film can be manually adjusted to a certain expected value (10–50 dB) by controlling the applied current and irradiation time. The GNPs-PLA Janus films can be applied in complex electromagnetic environments and have enormous research value and development potential in the field of controllable electromagnetic interference shielding.