Thesis Defense: Investigation of Graphene reinforced Polymer Composite materials for Electromagnetic Interference Shielding Applications 

In this work, various approaches have been adopted to develop microwave active (i.e., conducting, magnetic, semi-conducting, and di-electric) polymer composites materials to create high-performance, lightweight, and effective EMI shielding materials. Firstly, MWCNT was used to develop shielding materials because of their excellent electrical properties. To increase the shielding performance, hybrid composites are synthesized by the inclusion of rGO, barium and strontium hexaferrites, PANI-coated hexaferrite, and MWCNT with the magnetic component of EM waves resulting in an enhanced SET value for both BaFe12O19-PANI and SrFe12O19-PANI composites. Interfacial polarization and numerous reflections within the network generated in the composites also help to increase the SET value of the rGO/BaFe12O19-PANI and rGO/SrFe12O19-PANI composites[5]. Further, decorating Fe3O4nanoparticles on rGO layers and shielding performance with metallic oxides are studied; understanding the mechanism of shielding allows one to choose different fillers for different EM applications, and it also provides insight into designing shielding materials to achieve maximum shielding ability by blending different filler materials[6]. Also, functionalizing the GO with di-electric and semi-conducting particles, the polymer composite sheets embedded with rGO-BaTiO3 and rGO-ZnO coupled to a conductive MWCNT network. SET was computed by altering the weight ratio and thickness. For the developed composites, the highest SE achieved is 59.8 dB for rGO-BaTiO3 composites and 57.9 dB for rGO-ZnO composites[7].This study comprehensively explains the mechanisms underlying the different polymer composite materials and their EMI shielding capabilities. This multifaceted approach will aid in creating an EMI shielding material that is long-lasting and highly effective.