2021-11-29

The University of science and technology of China has made important progress in developing biomimetic nanocomposite films for space protection

By yqqlm yqqlm

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b877ae83e0cc567 - The University of science and technology of China has made important progress in developing biomimetic nanocomposite films for space protection

schematic diagram of preparation process of polyimide nano mica biomimetic composite membrane and its microstructure, mechanical properties and atomic oxygen resistance

recently, Academician Yu Shuhong of China University of science and technology has developed a new polyimide nano mica composite membrane material for space protection applications. The material adopts a unique bionic design, which has significantly improved its mechanical properties and space extreme environment tolerance. Inspired by the “brick mud” layered structure of natural mother of pearl, researchers cleverly designed and constructed polyimide mica nanocomposite film with double-layer nacre like structure, so that the top layer is distributed with more dense mica nano sheets. With the help of the intrinsic properties of mica and the advantages of being the most building unit, while effectively improving the mechanical properties of materials, the top layer is exposed to atomic oxygen The resistance to ultraviolet radiation and space debris has also been significantly improved. The research results were published in the international journal advanced materials under the title of “double layer nacre inspired polyimide mica nanocomposite films with excellent mechanical stability for Leo environmental conditions”. Pan Xiaofeng, a special associate researcher of our university, and Wu Bao, a doctoral student, are the co first authors of the paper, and Gao huailing, an associate researcher, and Professor Yu Shuhong are the corresponding authors

the researchers used the mica nanosheets (NAT. Commun. 2018, 9, 2974) developed by them in the early stage with excellent mechanical properties and UV shielding function and can be prepared in large quantities as building elements, and co assembled with polyimide precursors to obtain polyimide mica nanocomposite films. The superior intrinsic properties of mica were used to make up for the shortcomings of polyimide. Different from the previous single-layer structure design of nacre like nanocomposite film, in this study, the researchers constructed polyimide mica nanocomposite film with double-layer nacre like structure by changing the component distribution ratio and using the combination of spraying and thermal curing, so that its top layer has more dense mica nano sheet (Fig. 1a-f). This design strategy not only effectively improves the mechanical properties of the material, but also makes its upper surface more resistant to atomic oxygen, ultraviolet radiation and space debris

the research shows that the tensile strength, Young’s modulus and surface hardness of this new bionic composite film are 125 MPa, 2.2 GPA and 0.37 GPA respectively, which are 45%, 100% and 68% higher than that of pure polyimide film (Fig. 1g). Due to the unique double-layer mother of Pearl like structure and the inherent performance advantages of mica nano sheets, the obtained double-layer polyimide mica composite film shows better atomic oxygen resistance (erosion rate ≈ 0.17) × 10-24 cm-3 atoms-1), which is obviously superior to pure polyimide film, single-layer polyimide mica composite film with mother of Pearl structure and polyimide matrix composites previously reported. In addition, the UV aging resistance (313 nm) and high temperature stability (380oc) of the pure PI film were also significantly improved

this kind of polyimide mica nanocomposite film with double-layer mother of Pearl like structure is expected to replace the existing polyimide based composite film as an effective new spacecraft outer protective material for low orbit environment. The unique double-layer mother of Pearl structure design strategy proposed in this study also provides a new idea for the design and construction of other high-performance nanocomposites

this research was supported by the innovation research group funding project of the National Natural Science Foundation of China, the key projects of the National Natural Science Foundation of China, the frontier key projects of the Chinese Academy of Sciences, the special fund for basic scientific research business expenses of central universities, the collaborative innovation project of colleges and universities in Anhui Province and the joint fund for synchronous radiation of the University of science and technology of China

(National Research Center of microscale material science, College of chemistry and materials science, scientific research department)