Multilayer architected polymer nanostructure for microwave absorber-based EMI shielding

Reflection-based electromagnetic interference shielding materials, though effectively stop the radiation, redirect the interference to nearby electronic devices, creating secondary pollution. In this sense, it is better to use absorption-dominant lightweight and flexible materials with high shielding effectiveness. This paper reports the fabrication of a multilayered polymer nanocomposite for enhancing electromagnetic interference shielding applications through absorption. By using a doctor-blade technique, three individual layers of poly(vinylidene fluoride) based polymer nanocomposite, each with different fillers, were prepared and stacked together to form a 3 mm thick multilayered (four-layer) composite. The fillers were 5% Ag-decorated graphene nanoplatelets, acid-functionalized MWCNT, and barium hexaferrite. Between 8 and 18 GHz, this multilayered composite absorbs a maximum of 90% of incident microwave radiation, resulting in a shielding in the range of 20–45 dB. This structure is very useful for developing flat and lightweight absorbers. For comparison, a homogeneously prepared nanocomposite comprising all these three fillers is found to give a shielding of around 53 dB with a reflection ranging between 78% and 89%.