Flexible, stretchable and electrically conductive PDMS decorated with polypyrrole/manganese-iron oxide nanocomposite as a multifunctional material for high performance EMI shielding applications

Rapid growth in portable and wearable electronics requires high performance electromagnetic shielding materials that are lightweight, flexible, stretchable and electrically conductive to counter the problems of increasing electromagnetic pollutions. Absorption dominant microwave wrap-on shielding materials are in great demand for mitigating the effect of electromagnetic interference on devices and the environment. In this work we report preparation of a multifunctional composite that effectively combines the outstanding EMI shielding, electrical conductivity mechanical flexibility and magnetic properties of hybrid polymer nanocomposite systems for wearable electronics. Highly conductive Polypyrrole (PPy)/Manganese-Iron oxide (MnFe2O4) nanocomposites treated with para toluene sulphonic acid (PTSA) were incorporated into polydimethylsiloxane (PDMS) matrix to obtain a multifunctional hybrid structure. The incorporation of PTSA treated PPy- MnFe2O4 nanoparticles forms excellent conductive network and improves the electrical and magnetic properties of the composites. The PDMS based nanocomposite exhibit superior conductivity of 24.03 S/cm with robust mechanical properties such as Young's modulus (0.93 MPa) and tensile strength (2.62 MPa). Due to improved conductivity and magnetic attributes this PDMS based nanocomposite with 0.5 mm thickness shows absorption dominated superior electromagnetic shielding performance (EMI-SE of −21 dB corresponds to 99.21% of shielding efficiency) in X-band microwave frequencies. Further, these nanocomposite shields exhibit excellent stability in conductivity and EMI-SE values under mechanical stretching and bending. Apart from being an excellent shielding material, this PDMS based nanocomposite serves as a superior strain sensor, indicates multifunctional dimensions of this material. Owing to the features such as light weight, flexibility, stretchability, high conductivity, excellent EMI-SE as and superior strain sensing performance, these composites can be used in flexible and foldable devices as smart wrap-on shield.