Synthesis of flexible magneto-electric polyvinyl alcohol composites using hybrid filler particles of carbon quantum dots and cobalt nano for electromagnetic interference shielding application

The main objective of the study is to synthesis and characterization of flexible magneto-electric Polyvinyl Alcohol (PVA) composites for Electromagnetic Interference (EMI) shielding applications, by incorporating carbon quantum dots extracted from lychee fruit husks and cobalt nanoparticles sourced from Plectranthus amboinicus. Comprehensive mechanical, dielectrical, magnetic, and shielding tests were conducted to assess the performance of these novel materials. The mechanical characteristics of the composites were assessed to gauge their flexibility and robustness. In this regard, PV4 displayed a substantial tensile strength of 68 MPa, while PV6 exhibited an enhanced shore-D hardness rating of 47. PV6 demonstrates superior dielectric properties, including a higher dielectric constant and a lower loss tangent, which are crucial for optimizing EMI shielding efficiency. When it comes to magnetic characteristics such as magnetization, retentivity, and coercivity, the PV6 composite designation outperforms the other composites. Additionally, PV6 exhibits higher electromagnetic interference (EMI) shielding effectiveness, measuring at approximately 49.8 dB in the E band and 56.5 dB in the F band. Findings demonstrate that the integration of carbon quantum dots and cobalt nanoparticles into the matrix resulted in flexible composites with enhanced mechanical strength. The incorporation of cobalt contributed to notable magnetic properties, increasing the materials' magnetization and retentivity. The tests on electromagnetic interference (EMI) showed that the shielding effectiveness got improved. The composite materials were able to reduce interference from electromagnetic waves in the tested frequency ranges. These flexible magneto-electric PVA composites, developed using sustainable sources such as lychee fruit husks and Plectranthus amboinicus, exhibit promising potential for EMI shielding applications in diverse industries, including telecommunications, aerospace, and electronics, where reliable interference control is essential for optimal performance and safety.

Highlights

• Cobalt nanoparticles sourced from Plectranthus amboinicus.
• Carbon quantum dots are prepared from lychee fruit husks via controlled pyrolysis.
• High tensile strength PVA composites prepared.
• Highest dielectric constant of 8.2 achieved for composite PV6.
• Higher wave shielding up to 56.5 dB achieved in “E” band.