PhD Thesis Colloquium: Mr. Amit Malakar 10/09/25)
Thesis title:
Green EMI Shielding Composites: Absorption Dominance Through Structure and Composition
Faculty advisor(s):
Prof. Suryasarathi Bose
When?
10th September, 2025 (Wednessday), 2:30 PM (India Standard Time)
Where
KPA Auditorium, Department of Materials Engineering
Abstract:
The rapid miniaturization of modern electronic devices has intensified electromagnetic interference (EMI), which adversely affects the performance of components and systems. Conventional metallic shielding materials, although effective, face critical limitations including high density, corrosion, reflection-dominated mechanisms, and processing challenges. To address these shortcomings, this thesis,“Green EMI Shielding Composites: Absorption Dominance Through Structure and Composition”, investigates the design of functional nanomaterial-based, multilayered polymer composites engineered for absorption-dominated EMI shielding.
The research begins with polyvinyl alcohol-based composites incorporating carbon nanotubes (CNTs) and copper polyoxometalates (Cu-POMs), fabricated via vacuum-assisted filtration, achieving ~45 dB shielding with ~90% absorption in the X-band. Subsequently, electrostatic self-assembly on interpenetrating polymer networks (IPN) reinforced with graphene oxide yields lightweight constructs with outstanding specific shielding effectiveness (8637 dB cm² g⁻¹), complemented by self-healable polymer coatings for durability. Further, a multilayered PU-based architecture integrating conductive CNT layers and magnetic Ni/Co alloy microflowers, with an IPN interlayer, demonstrates flexible, twistable, and conformable composites achieving ~35 dB shielding in the K-band with an A/R ratio ~3.0 and green shielding index ~2.64, suitable for 5G and wearable electronics.
In the final study, a flexible polyester–MWCNT sandwich composite incorporating a porous laser-scribed carbon (LSC) middle layer is developed, replacing toxic isocyanates in PU with citric acid. This eco-friendly structure exhibits absorption–reflection–absorption mechanisms, surpassing the commercial benchmark (> − 20 dB) across X, Ku, and K bands, with A/R > 1 and enhanced green shielding index.
Overall, the thesis demonstrates how architectural and compositional design of green multilayered composites enables tunable, sustainable, and high-performance EMI shielding solutions for next-generation electronics.
Publication:
Engineering a Green, Flexible Shield: Multilayered sandwich composites consisting of laser scribed carbon and polyester MWCNT in Absorption-Dominated EMI Protection. (manuscript under preparation)
Amit Malakar, A. Mohanty, S. Bose*, Porous microflower-like Carbon encapsulated Ni/Co alloy incorporated Polyurethane based flexible, self-cleaning multilayered films for EMI shielding in K-band, and wearable electronics, (ACS Applied Engineering Material, 2025, just accepted).
Amit Malakar, S. Mandal, R. Sen Gupta, V. Kashyap, Rishi Raj, K. Manna, S. Bose*, ‘Donor–acceptor’,‘interpenetrating polymer network’ and ‘electrostatic self-assembly’ work in tandem to achieve extraordinary specific shielding effectiveness, (Nanoscale, 2024).
Amit. Malakar, S. Mandal, R. Sen Gupta, S. Islam, K. Manna and S. Bose*, Polyoxometalates immobilized carbon nanotube constructs triggered through host-guest assembly results in excellent electromagnetic interference shielding, (Nanoscale, 2023).