Multilayer composites containing anisotropic structured aerogels: a strategy for enhancing the electromagnetic shielding absorption mechanism and achieving multi-functional integration
Abstract
Multifunctional composite materials have shown great potential in addressing emerging challenges, such as electromagnetic radiation pollution. By designing a rational scheme and arranging the distribution of conductive multiwalled carbon nanotubes (MWCNTs) and a liquid metal (LM), a multifunctional composite material with a conductivity gradient is constructed. We successfully developed a multilayer shielding composite material (CX1CX2MY) that meets the design requirements using simple freeze-drying technology and solution casting, and coating techniques. The composite material constructs a sequence of multilayer shielding network structures, allowing electromagnetic waves to undergo a specific “absorption–reflection–reabsorption” process, effectively reducing the reflection of electromagnetic waves and achieving a good electromagnetic interference shielding effect (EMI SE). At the X-band, when the absorptivity (A) value is 0.82, the composite material can achieve an EMI SE of 35.74 dB, and when the A value is 0.36, it can achieve 67.17 dB, demonstrating excellent electromagnetic shielding performance. The composite material has excellent mechanical properties and electrical properties. An effective Joule heating effect can achieve a high temperature of 80 °C at a low voltage of 3 V. The sensitive pressure sensing effect can achieve a resistance change ratio of 558% under slight pressure. This composite material provides a promising solution for multifunctional integrated electromagnetic interference shielding.