A Comprehensive Review on Carbon-Based Polymer Nanocomposite Foams as Electromagnetic Interference Shields and Piezoresistive Sensors

Polymer-based nanocomposite foams containing carbonic fillers have greatly facilitated scientific research efforts in electromagnetic interference (EMI) shielding, as well as piezoresistive sensing devices. The carbon-based fillers not only provide superior EMI shielding properties and extraordinary gauge factor but also offer critical advantages of electromagnetic wave absorption and supreme pressure sensitivity. Currently, electromagnetic signal interference has become a severe challenge for which wireless communication is responsible. Furthermore, considering the rapid development of the flexible electronics industry, demands for piezoresistive sensors comprising a wide range of responses and increased sensitivity are considerably increased. The present work reviews recent developments and breakthroughs in polymer foam composites primarily concentrating on various high-performance carbonic nanomaterials, including graphene, carbon nanotubes (CNTs), carbon black, and their hybrid fillers. Moreover, demands for further improvement in case of technical issues, compatibility, or synergic effect of type of nanofiller on the polymer host, as well as the influence on microstructure and electrical properties of foam materials, have been elucidated in the review. To be more specific, the effect of carbonic filler size and shape, as well as its electric, microstructure, and mechanical properties, in fabricating high-performance piezoresistive and EMI shielding polymeric composite foams is covered. In addition, cutting-edge developments in carbonic polymer nanocomposite foams in EMI shielding and piezoresistive sensor applications are highlighted. To be specific, available methods for tailoring appropriate microstructure and electrical and mechanical properties in EMI shielding materials and pressure sensors, current technological challenges in fabricating and developing nanocomposite foams for such mentioned applications, and future perspectives are discussed.