Recent advances in novel aerogels through the hybrid aggregation of inorganic nanomaterials and polymeric fibers for thermal insulation

Aerogel is a nanoporous solid material with ultrahigh porosity,ultralow density,and thermal conductivity,which is considered to be one of the most promising high-performance insulation materials today.However,traditional pure inorganic aerogels(i.e.,silica aerogel)exhibit inherent structural brittleness,making their processing and handling difficult,and their manufacturing costs are relatively high,which limits their large-scale practical use.The recently developed aerogel based on polymer nanofibers has ultralow thermal conductivity and density,excellent elasticity,and designable multifunction.More importantly,one-dimensional polymer nanofibers are directly used as building blocks to construct the network of aerogels via a gelation-free process.This greatly simplifies the aerogel preparation process,thereby bringing opportunities for large-scale aerogel applications.The aggregation of inorganic nanomaterials and polymer nanofibers is considered to be a very attractive strategy for obtaining highly flexible,easily available,and multifunctional composite aerogels.Therefore,this review summarizes the recent advances in novel aerogels through the hybrid aggregation of inorganic nanomaterials and polymeric fibers for thermal insulation.The main processing routes,porous microstructure,mechanical properties,and thermal properties and applications of these aerogels are highlighted.In addition,various future challenges faced by these aerogels in thermal insulation applications are discussed in this review.