An Efficient and Flexible Preparation Method for Multilayer Functional Aramid Nanofibers-Based Aerogel

As an ideal candidate for lightweight applications, aramid nanofibers(ANFs)-based aerogel has outstanding thermal stability, corrosion resistance and great mechanical properties. However, some existing complex application scenarios put forward higher requirements for its performance, and multi-functional integration has become its important development direction. Since the intrinsic properties of fillers in the composite aerogel will greatly affect aerogel’s functionality, the structural configuration should be considered at the same time. Herein, we have proposed a preparation method for multilayer functional ANFs-based aerogel through multiple cycle casting and freezing, weak acid enhanced protonation and freeze-drying processes, in which the specific properties of the single functional layer are enhanced by one functional filler and the multifunction integration is achieved by the stacking of multiple functional layers. The prepared representative sample: SiC-CNT-SiC/ANF aerogel exhibits the characteristics of low density, great mechanical properties, excellent heat insulation and flame retardant effect, and good self-heating function. And the four-layer aerogel (CNT-SiC-SiC-SiC/ANF) can not only meet the rapid self-heating in CNT/ANF layer, but also has the overall efficient thermal insulation function. This efficient and flexible preparation method will provide more possibilities for preparing more types of multifunctional ANFs-based aerogels, making them better suitable for complex application scenarios.