Gravity-Induced Formation of Flexible Janus Cellulose-Based Aerogels for Synergistic Enhancement of Electromagnetic Interference Shielding and Thermal Conductivity

Although cellulose-based aerogels possess lightweight and porous advantages, their brittle pore wall structure makes it challenging to simultaneously achieve high electromagnetic shielding performance, excellent mechanical flexibility, and effective thermal management. This study employs an emulsion template method combined with a gravity-induced layering strategy to fabricate a Janus-structured BMX flexible aerogel film to solve this issue. Flexible and amphiphilic PDMS-NH2 is used to stabilize the emulsion and further participate in forming a flexible pore wall. The resulting aerogel film exhibits a gradient structure with a honeycomb-like porous upper layer and a lamellar porous bottom layer. This architecture not only enhances electromagnetic wave absorption loss through multiple reflection mechanisms but also promotes mechanical strength and in-plane heat conduction via the oriented layer. The optimal sample, with a thickness of 213 μm, achieves an average EMI SE of 43.7 dB in the X-band, an in-plane thermal conductivity of 0.286 W·m-1·K-1, and a tensile strength of 5.4 MPa. It also demonstrates high efficiency as a thermal interface material for chip cooling. This work provides new insights for multifunctional integrated material design targeting next-generation flexible high-power electronic devices.