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<p>The growing reliance on wireless technologies for communication has led to an increase in electromagnetic pollution, which poses various challenges, ranging from degrading the performance of electronic devices to an elevated risk of health issues. Effective electromagnetic shielding materials are crucial for protecting against the harmful effects of unwanted electromagnetic radiation. In this study, we investigate the electromagnetic interference (EMI) shielding performance of polydimethylsiloxane (PDMS) composites embedded with varying concentrations of carbon black (CB) and Fe<sub>3</sub>O<sub>4</sub>. The composites were fabricated through a straightforward process involving mechanical mixing, ball milling, and hot pressing under high temperature and pressure. Dielectric analysis of the composites was performed in the range of 10<sup>7</sup>–10<sup>9</sup>&#xa0;Hz to understand the permittivity and impedance characteristics of the composites. Negative permittivity was observed for PDMS-CB (PC) composites and PDMS-CB-Fe<sub>3</sub>O<sub>4</sub> (PCF) composites, which was attributed to both plasmonic oscillations and bound electron resonance. Impedance analysis and equivalent circuit modelling revealed the inductance effect to be a major contributor to negative permittivity behaviour. The shielding efficiency (SE) of the composites was analysed in a frequency range of 18–26.5&#xa0;GHz to understand the dependence of shielding efficiency on filler loading and frequency. Fe<sub>3</sub>O<sub>4</sub>-incorporated composites exhibited enhanced absorption capabilities, which are essential for modern EMI shields. PCF 3 (3 wt.% Fe<sub>3</sub>O<sub>4</sub>) displayed better absorption and the highest shielding efficiency of 41.3&#xa0;dB for a thickness of 1.652&#xa0;mm, which corresponds to 99.99% attenuation. The synergy between dielectric losses and magnetic losses offered by CB and Fe<sub>3</sub>O<sub>4</sub>, respectively, resulted in efficient microwave absorption. Further, the mechanical properties of the composites were also investigated, and they were able to withstand high packing loads with good flexibility.</p>

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Conducting Carbon Black and Fe3O4-Reinforced Polydimethylsiloxane Composites for Electromagnetic Interference Shielding

  • 期刊论文

  • 发表日期：

    2025年10月13日

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  • Devika S J,
  • Aiswarya Kallyani,
  • Sajeev Damodarakurup,
  • Bindu P. Nair,
  • Subodh Ganesanpotti

摘要

The growing reliance on wireless technologies for communication has led to an increase in electromagnetic pollution, which poses various challenges, ranging from degrading the performance of electronic devices to an elevated risk of health issues. Effective electromagnetic shielding materials are crucial for protecting against the harmful effects of unwanted electromagnetic radiation. In this study, we investigate the electromagnetic interference (EMI) shielding performance of polydimethylsiloxane (PDMS) composites embedded with varying concentrations of carbon black (CB) and Fe3O4. The composites were fabricated through a straightforward process involving mechanical mixing, ball milling, and hot pressing under high temperature and pressure. Dielectric analysis of the composites was performed in the range of 107–109 Hz to understand the permittivity and impedance characteristics of the composites. Negative permittivity was observed for PDMS-CB (PC) composites and PDMS-CB-Fe3O4 (PCF) composites, which was attributed to both plasmonic oscillations and bound electron resonance. Impedance analysis and equivalent circuit modelling revealed the inductance effect to be a major contributor to negative permittivity behaviour. The shielding efficiency (SE) of the composites was analysed in a frequency range of 18–26.5 GHz to understand the dependence of shielding efficiency on filler loading and frequency. Fe3O4-incorporated composites exhibited enhanced absorption capabilities, which are essential for modern EMI shields. PCF 3 (3 wt.% Fe3O4) displayed better absorption and the highest shielding efficiency of 41.3 dB for a thickness of 1.652 mm, which corresponds to 99.99% attenuation. The synergy between dielectric losses and magnetic losses offered by CB and Fe3O4, respectively, resulted in efficient microwave absorption. Further, the mechanical properties of the composites were also investigated, and they were able to withstand high packing loads with good flexibility.