Aerogel fibers are an emerging class
of ultralightweight
materials,
which, compared to conventional bulk monolithic and aerogel films,
provide better flexibility and extensibility. Despite the recent advancements
in this field, due to their highly porous structure, their mechanical
properties can be deteriorated. Inspired by the textile industry,
we report the development of aerogel fiber bundles with twisted structures
as a promising strategy to enhance the mechanical performance and
practicality of aerogel fibers. Polyimide (PI) aerogel fibers were
prepared via the sol–gel confined transition method. The fibers
showed a unique nanostructured assembly with high specific surface
area, excellent optical transparency, outstanding flexibility at diverse
extreme conditions, self-extinguishing behavior, and superior thermal
insulation performance. Using PI aerogel fibers as the backbone, aerogel
fiber bundles in various configurations were designed and fabricated.
A systematic study was performed to analyze the effect of design parameters
on the mechanical performance of the bundles. Results revealed an
optimal twist level for bundles, leading to a peak in mechanical properties
across various bundle configurations. The observed improvement in
mechanical properties was attributed to increased fiber-to-fiber binding
strength, enhanced friction, and interlocking mechanism of fibers,
underscoring the potential of the optimized twist level for enhancing
the performance of aerogel fiber bundles. Overall, the development
of aerogel fiber bundles holds great promise in revolutionizing the
production of high-performance ultralightweight materials for thermal
management applications.