Multilayer polymeric nanocomposites for electromagnetic interference shielding: fabrication, mechanisms, and prospects

The ever-increasing proliferation of wireless communication systems and modern electronics arouses concerns regarding electromagnetic pollution. Such concerns become even more vital considering the rapid development of compact and flexible electronics. These concerns call for the integration of lightweight EM shielding materials with enhanced thermal and mechanical characteristics in advanced electronics. In this regard, multilayer polymer nanocomposites have been developed as a novel class of functional electromagnetic interference (EMI) shielding materials. Up to now, this new class of EMI shields has showcased several key features, including enhanced flexibility, thermal properties, and EMI shielding effectiveness (EMI SE) that can meet the current demands of the industry. More interestingly, the multilayer strategy is capable of transcending the EMI shielding mechanism from reflection to absorption. This feature article provides a comparative and balanced discussion of recent advances in multilayer EMI shields. The EMI shielding mechanisms, choice of materials, and the rationale behind the improved mechanical and thermal properties of the multilayer shields are also highlighted. The outlook provided in this review points out the promising properties and remarkable tunability of the multilayer shields that introduce them as versatile substitutes for traditional metallic or even single-layer polymeric shields. This review paper promises that the future of multilayer EMI shields is boundless, and soon, this novel class of EMI shields will be utilized in various electronic devices and radiation source fields on a large scale. Fabrication of multilayer EMI shield opens a creative avenue for designing and constructing flexible nanocomposite films simultaneously featuring excellent EMI shielding performance, fascinating heat removal ability, and robust mechanical properties.