biostudies-literatureShi TFoundation of Young Scholars of Western China, Chinese Academy of SciencesBeijing Natural Science Foundatione2411758https://www.ebi.ac.uk/biostudies/studies/S-EPMC11791978biostudies-literatureUnknown12(5)There is an emerging requirement of advanced functional materials for simultaneous thermal protection and electromagnetic wave-transparent transmission applications. A novel polyimide (PI) aerogel-based sandwich-structural composite is developed to meet such a requirement in this study. This composite is based on a unidirectional fluorinated PI (FPI) aerogel as a lower layer, a nondirectional conventional PI aerogel as a middle layer, and a nondirectional FPI aerogel/paraffin phase-change composite as an upper layer. The lower layer exhibits a unique unidirectional porous microstructure and an ultralow dielectric constant of 1.04. The upper layer possesses a dynamical temperature regulation capability thanks to its loaded paraffin having a high latent heat capacity of 242.7 J g<sup>-1</supAdvanced science (Weinheim, Baden-Wurttemberg, Germany)Sandwich-Structured Fluorinated Polyimide Aerogel/Paraffin Phase-Change Composites Simultaneously Enables Gradient Thermal Protection and Electromagnetic Wave Transmission.PMC117919782242049Liu HQian ZJing JTian GShi TWang XWu GfalseSandwich-Structured Fluorinated Polyimide Aerogel/Paraffin Phase-Change Composites Simultaneously Enables Gradient Thermal Protection and Electromagnetic Wave Transmission.There is an emerging requirement of advanced functional materials for simultaneous thermal protection and electromagnetic wave-transparent transmission applications. A novel polyimide (PI) aerogel-based sandwich-structural composite is developed to meet such a requirement in this study. This composite is based on a unidirectional fluorinated PI (FPI) aerogel as a lower layer, a nondirectional conventional PI aerogel as a middle layer, and a nondirectional FPI aerogel/paraffin phase-change composite as an upper layer. The lower layer exhibits a unique unidirectional porous microstructure and an ultralow dielectric constant of 1.04. The upper layer possesses a dynamical temperature regulation capability thanks to its loaded paraffin having a high latent heat capacity of 242.7 J g<sup>-1</sup2025-01-01T00:00:00Z2025 Feb2025-04-19T05:59:56.771Z2025-04-19T05:59:56.771ZS-EPMC117919783963980110.1002/advs.202411758