PDMS-Based Nanocomposite for EMI Shielding application

Abstract

Lightweight, flexible, and easy-to-integrate solutions are in great demand in electronic devices. The present work deals with the preparation of Poly dimethyl siloxane (PDMS) based nanocomposite for suppressing electromagnetic interference (EMI). This work is broadly divided into five chapters. The first chapter discusses the state-of-the-art literature on polymeric nanocomposites in general and PDMS-based composites in particular for EMI shielding applications. The second chapter discusses the materials and methods used for the preparation of nanocomposite in this study. The third chapter discusses the synthesis and characterization of MoO3-MWCNTs conjugates and their composites with PDMS. The bulk electrical conductivity and the EMI shielding performance of the nanocomposites are discussed in this chapter. The challenges associated with the curing of PDMS are also discussed in this chapter. This filler system exhibited shielding effectiveness of SET ca. 25 dB for a 1 mm thick sample. The fourth chapter highlights the synthesis and preparation of hybrid fillers consisting of carbonaceous fillers such as rGO and MWCNT and MoS2 using a hydrothermal technique. When incorporated in PDMS and cured using condensation curing, the composites showed SE of ca. 25 dB for a 1 mm thick sample. In the last chapter, the EMI shielding performance of multi-layered stacking of previously prepared sheets was evaluated. The composite with the best configuration showed SET up to 40 dB for a 3 mm thick sample. In summary, two different filler systems were explored in this thesis for the efficient absorption of EM waves. In this thesis, two different crosslinking mechanisms (addition and condensation curing) were explored based on the chemistry of the filler system. The composite was further characterized for AC conductivity, EMI shielding and UV blocking characteristics.