Graphene-Skinned Fiber with Fine-Tunable Electrical Resistance via Radical and Substrate Engineering for Electromagnetic-Thermal Fabric

This work demonstrates a radical-manipulation strategy for synthesizing graphene (Gr)-skinned SiO₂ fabric via low-pressure chemical vapor deposition using methanol precursor. Controlled pyrolysis at high temperature regulated C₁/C₂/C₆ radical ratios, enabling microstructure engineering. Substrate effects governed bilayer evolution. SiO₂ imposed lower adsorption energy of C₁ and higher diffusion barriers of radical compared to Gr, promoting edge defects in subsurface G1-type Gr layers, whereas reduced substrate constraints facilitated low-defect G2-type Gr growth on top of G1-type Gr. Synergistic control of gas-phase kinetics and substrate dynamics enabled fine-tunable sheet resistance (26-150 Ω sq^-1), establishing Gr-skinned fibers as multifunctional platforms for integrated electromagnetic-thermal management systems. When addressing the needs of electromagnetic communication and electrothermal deicing, laser-etched band-pass frequency selective surface structures of Gr-skinned fabric were fabricated to achieve electromagnetic wave (EMW) transmittance while maintaining Joule heating capability. A sandwich structure was prepared by laminating the Gr-skinned fabric with EMW transparent sheets exhibiting voltage-dependent transmittance, simultaneously sustaining broadband transmission and effective heating. This work demonstrates a strategy to mitigate the longstanding conductivity-EMW transparency trade-off in Gr-functionalized fibers through a multiscale engineering that coordinates microscopic structural regulation with macroscopic patterning, thereby unlocking next-generation smart composites for 5G/6G wearables, aerospace radomes, and beyond.