Extreme-environment applications such as deep-space exploration, aerospace engineering, firefighting, and emergency rescue require protective materials that can withstand intense heat, repeated compression, and sudden impact while remaining lightweight and flexible. Aerogels are attractive candidates because their highly porous structures provide extremely low density and excellent thermal insulation. However, conventional nanofiber aerogels are often mechanically fragile, and improving their strength can compromise flexibility or introduce additional heat-transfer pathways. Achieving thermal insulation, mechanical robustness, and impact resistance within a single lightweight material therefore remains a major challenge.
A research team led by Professor Xiaohong Qin at Donghua University has developed a bamboo-inspired polyimide composite aerogel that addresses this long-standing trade-off. The new material, referred to as PAI, integrates molecular crosslinking, nanofiber interlocking, and porous scaffold support across multiple length scales. This cross-scale architecture enables the aerogel to combine structural rigidity with elastic deformability, providing integrated thermal and mechanical protection under harsh conditions. The study, entitled “Achieving Rigid-Flexible Coupling in Polyimide Aerogels via Biomimetic Cross-Scale Architecture for Extreme Condition Protection,” is reported in Nano Research on June 29, 2026.
Bamboo is both strong and flexible because its structural components are connected and interlocked across multiple scales. At the molecular level, cellulose, lignin, and hemicellulose form interconnected networks. At larger scales, highly organized fibers and scaffold-like structures reinforce bamboo nodes and transition regions, helping the material distribute stress and resist deformation. Inspired by these natural load-bearing and energy-dissipation mechanisms, the Donghua University team constructed a similar hierarchical architecture within polyimide aerogels. At the molecular scale, the flexible crosslinker 1,3,5-tri(4-aminophenoxy)benzene was introduced to connect polyimide chains. These flexible molecular junctions restrict excessive chain slippage while preserving sufficient conformational freedom for reversible deformation. At the nanoscale, hydrophobic silica particles were used to guide the bending and interlocking of polyimide nanofibers, creating a physically entangled network with multiple reinforcing junctions. At the microscale, directional freezing and thermal imidization generated aligned pores containing interlayer nanofiber supports. These scaffold-like connections help disperse external stress, delay local collapse, and maintain the integrity of the porous framework during compression and impact. The resulting PAI achieved a tensile modulus of 4.17 MPa and a compressive modulus of 138 kPa. After 100 lateral compression cycles, its cumulative plastic deformation remained below 7%, while its maximum stress retention reached 99%. The material also maintained more than 85% recovery after 1,000 compression cycles, demonstrating excellent elastic durability and resistance to fatigue. The aerogel showed strong impact-buffering performance. In drop-impact tests, the multiscale network reduced the peak transmitted force and extended the impact duration, allowing mechanical energy to be dissipated through nanofiber bending, interlayer contact, and reversible structural deformation. When incorporated into protective equipment, the PAI reduced the transmitted impact force by more than 83% while maintaining stable mechanical performance after repeated loading.
The researchers also evaluated the material under extreme-temperature conditions. Cyclic compression tests were conducted in liquid nitrogen at −196 °C and in a high-temperature environment at 175 °C. At cryogenic temperature, the PAI exhibited a slightly higher compressive strength because the reduced mobility of the polymer chains produced a stiffer response. At high temperature, the compressive strength decreased moderately as increased chain mobility caused thermal softening. Despite these temperature-dependent changes, the stress–strain curves remained stable after 1, 10, and 100 cycles in both environments, demonstrating that the aerogel retained mechanical integrity and elastic resilience across a broad temperature range. In addition to its mechanical performance, the PAI has a density of only 0.045 g·cm⁻³ and a thermal conductivity of 38 mW·m⁻¹·K⁻¹. Its hierarchical porous network restricts gas-phase heat conduction, interrupts solid heat-transfer pathways, and enhances the scattering of thermal radiation. These effects allow the material to provide efficient thermal insulation without sacrificing structural robustness. The aerogel also exhibited strong flame-retardant performance. Cone calorimetry showed a peak heat release rate of 9.36 kW·m⁻² and a total heat release of 8.55 MJ·m⁻², representing reductions of 47.7% and 19.3%, respectively, compared with a conventional non-crosslinked polyimide aerogel.
To demonstrate its practical potential, the researchers integrated the PAI with polyimide–aramid fabric to construct a lightweight protective system. The aerogel served as the reinforcing and insulating core, while the heat-resistant fabric formed the outer layer. The resulting structure combined impact mitigation, thermal insulation, flame resistance, and mechanical durability, illustrating its potential for firefighting garments, aerospace protection, and other applications involving simultaneous thermal and mechanical hazards.
Other contributors to the study include Bin Wang, Junze Guo, Hongfang Liu, Maorong Zheng, Ailin Li, and Liming Wang from the College of Textiles and the Key Laboratory of Textile Science and Technology, Ministry of Education, at Donghua University in Shanghai, China.
This work was supported by the National Key Research and Development Program of China under grant numbers 2023YFC3011701 and 2023YFC3011700.
DOI Link:
https://doi.org/10.26599/NR.2026.94908982
About Nano Research
Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 8,000 articles. In 2025 InCites Journal Citation Reports, its 2025 IF is 9.4 (8.3, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.
Nano Research
Achieving rigid-flexible coupling in polyimide aerogels via biomimetic cross-scale architecture for extreme condition protection
29-Jun-2026