Carbon nanotube (CNT) films possess lightweight and flexible properties, along with scalable fabrication and easy integration, which render them promising candidates for impact protection. Nevertheless, their practical application is severely restricted by insufficient mechanical strength. Such drawbacks stem from intrinsic structural imperfections. Various structural optimization strategies have been developed to improve nanotube alignment, packing density and defect elimination, yet the achieved mechanical performance still falls short of theoretical expectations.
The research team led by Yuanyuan Li from Soochow University constructed a bio-inspired nanonetwork structure inspired by natural hierarchical architectures and achieved ultrahigh dynamic toughness of carbon nanotube composite films. The designed nanonetwork delivers efficient load transfer and strong interfacial interaction to overcome weak van der Waals forces between carbon nanotubes. Previous researches on carbon nanotube fibers prove that the integration of progressive stretching and p‑phenylene benzobisoxazole (PBO) infiltration optimizes interfacial adhesion, orientation and densification, and further elevates mechanical properties. PBO nanofibers are promising candidates for fabricating chemically crosslinked reinforcing networks.
They proposed a bioinspired nanonetwork strategy integrating precisely controlled stretching and PBONF interlocking to prepare ultra-strong and tough PBO-CNT composite films. This approach addresses the key structural drawbacks of conventional CNT films.
The interfacial engineering and reinforcement mechanism between CNT and PBO in film structures remain poorly understood. The dynamic mechanical behaviors including stress-strain response and damage evolution of such composite films are largely unexplored. This knowledge gap restricts the development of CNT films for applications requiring superior dynamic performance such as impact protection. By forming dense interconnected crosslinked networks within aligned CNTs, PBONFs mimic natural structures to achieve continuous stress redistribution and restrain crack propagation, offering a feasible way to simultaneously improve strength, toughness and damage tolerance of CNT-based materials.
Stretching duration and draw ratio are accurately regulated in chlorosulfonic acid (CSA) to prepare highly aligned and densified CNT films. Repeated stretching cycles facilitate nanotube orientation and reduce random entanglement, while appropriate draw ratio maintains favorable packing density without fracture or inadequate alignment. The density of CNT films rises from 0.56 to 0.94 g·cm⁻³. The fracture strength and elastic modulus reach 1.04 ± 0.06 GPa and 36.99 ± 1.8 GPa respectively.
PBO nanofibers are introduced into highly oriented compact CNT films with optimized dispersion concentration and treatment time to form interfacially interlocked nanonetwork composites. PBO nanofibers uniformly infiltrate pores and defective regions of CNT frameworks and build bridging structures between adjacent CNT bundles to form connecting nodes. Analogous to macroscopic fishing nets composed of lines, joints and meshes, aligned CNT bundles serve as primary load-bearing units and PBO-induced joints act as connecting components, jointly forming continuous interlocked networks. The stretchable open structure facilitates uniform distribution of PBO nanofibers throughout the film, forming robust chemically crosslinked nanonetworks and boosting stress transfer and interfacial cohesion.
The synergy of physical arrangement and chemical interlocking endows the composite films with outstanding dynamic mechanical properties. The tensile strength reaches 4.92 ± 0.2 GPa and toughness hits 118.96 ± 9.78 MJ·m⁻³, increasing by 3954.39% and 1060.59% compared with pristine CNT films. This work clarifies the reinforcement mechanism of PBO-interlocked CNT films under dynamic loading. It also provides a scalable and controllable route for high-performance protective nanomaterials, laying a foundation for commercial application in advanced impact protection systems.
The author of this paper is Chenyang Duan from the College of Textile and Clothing Engineering, Soochow University. Other contributors include Yuanyuan Li, Wei Zhu, Lin Wan, Zhengqiang Lyu and Dongmei Hu from the College of Textile and Clothing Engineering, Soochow University, and Suzhou Institute of Nano-tech and Nano-bionics.
This work is supported by the Youth Innovation Promotion Association CAS and China Textile Industry Federation Science and Technology Guidance Project (2024028).
DOI Link:
https://doi.org/10.26599/NR.2026.94908843
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Nano Research
Bioinspired nano-fishnet structural construction for ultra-high dynamic toughness of carbon nanotube composite films
27-Jul-2026