Facile Preparation of Continuous and Porous Polyimide Aerogel Fibers for Multifunctional Applications

Abstract

High-performance aerogel fibers with high porosity, ultralow density and thermal conductivity, and good flexibility are attractive candidates for the next generation of effective thermal insulation, efficient personal thermal management, and other functional applications. However, most previously reported aerogel fibers suffered from either limited working temperatures, weak mechanical properties, or complex manufacturing processes. In the present work, a facile wet-spinning technique combined with freeze-drying was developed to fabricate strong polyimide aerogel fibers (PAFs) based on organo-soluble polyimide. Attributed to the unique "porous core−dense sheath" morphology, the PAFs exhibited excellent mechanical properties with an optimum tensile strength of 265 MPa and an initial modulus of 7.9 GPa at an ultimate elongation of 65%, representing the highest value for aerogel fibers reported so far. Moreover, the PAFs possess high porosity (>80%) and high specific surface area (464 m 2 g −1 ), which render the woven PAF fabrics with excellent thermal insulation properties within a wide temperature range (−190 to 320 °C) and potential applications for thermal insulation under harsh environments. Additionally, a series of functionalized aerogel fibers or their fabrics based on PAFs, including phase-change fabrics with a thermoregulation function and electromagnetic shielding (EMI) textiles with a high EMI SE value, have been successfully fabricated for expanding their potential applications. Overall, this novel aerogel fiber sheds light on a promising direction for developing the next generation of high-performance thermal insulation and multifunctional fibers and textiles.

Flexible engineering of advanced phase change materials

“…Integrating personal thermoregulation technologies into wearable textiles has enabled extensive and profound technological breakthroughs in energy savings, thermal comfort, wearable electronics, intelligent fabrics ( Peng and Cui, 2020 ; Tabor et al., 2020 ). Nevertheless, previous studies have suffered from long-standing issues such as limited working temperature, poor comfort, and weak textile reliability ( Gu et al., 2020 ; Li et al., 2021b ). Encapsulating PCMs into fibers is a facile and effective approach to solve the leakage problem and improve the thermal performances of flexible textiles ( Tang et al., 2018 ).…”

Wearable and Robust Polyimide Hydrogel Fiber Textiles for Strain Sensors

“…Compared with aliphatic polymers, aromatic polyimides (PIs) have rigid and conjugated molecular chains, possessing excellent mechanical properties and outstanding chemical resistance, which have been widely used in the aerospace, electronics, and fire safety industries. Due to the diversities of the monomer structures for PIs and different solution properties, many types of PI materials have been developed such as films, resins, compact fibers, and even aerogel fibers . However, continuous fabrication of PI hydrogel fibers has not yet been reported.…”

“…Due to the diversities of the monomer structures for PIs and different solution properties, many types of PI materials have been developed such as films, 20 resins, 21 compact fibers, 22 and even aerogel fibers. 23 However, continuous fabrication of PI hydrogel fibers has not yet been reported. Although a type of PI ionogel 24 was prepared to be used in strain sensors under extreme conditions, they were not suitable for the continuous process due to the extremely rapid sol−gel transition process.…”

Robust Silica-Bacterial Cellulose Composite Aerogel Fibers for Thermal Insulation Textile

“…Freeze spinning and wet spinning are the most commonly reported methods used to prepare aerogel fibers [ 32 ]. The raw materials of the aerogel fibers are typically synthetic polymers [ 33 ], natural polymers [ 34 ], graphene oxide [ 35 ], or their composites [ 36 ]. Although some studies have reported on inorganic oxide (e.g., SiO 2 ) aerogels, their tensile strength generally does not exceed 0.5 MPa [ 27 , 37 ], which is much lower than that of the previously mentioned fibrous aerogels.…”