This paper reports an ultra-thin, ultra-strong, ultra-soft thermally stable film with metal-like mechanical properties, namely unprecedented tensile strength (300.5 MPa), high Young's modulus (13.6 GPa) and excellent Folding resistance (>10000 times). More importantly, this composite film has an excellent electromagnetic wave shielding effect, which can eliminate> 99% of electromagnetic waves. There are great prospects for practical applications in military and aerospace electronic devices and wearable device applications.
With the popularization of electronic equipment and the rapid development of communication technology, electromagnetic radiation is regarded as a serious problem, which not only endangers the normal operation and service life of equipment, but is also harmful to human health. Therefore, the research on electromagnetic shielding materials has attracted extensive attention. Metal materials have ultra-high ruggedness and excellent conductivity, and are the traditional choice for electromagnetic interference (EMI) shielding. Their high density, poor flexibility, and poor corrosion resistance have limited their widespread use, especially In a harsh environment. Two-dimensional (2D) transition metal carbide/carbonitride (ie, MXene) is considered a promising alternative to EMI shielding, with lightweight characteristics, high electrical conductivity, and excellent corrosion resistance. However, due to the weaker in-plane van der Waals interaction between adjacent two-dimensional (2D) MXene nanosheets, the macro-assembly structure is weakly bonded, which also leads to the brittleness of the film. In some extreme environments, this is still It is the bottleneck of its potential application. In general, the ideal protective material for extreme conditions EMI shielding should integrate all outstanding multi-functional functions, including high stability, good flexibility, temperature resistance and corrosion resistance, which is still very challenging.
In response to the above problems, researchers from Sichuan University and Nanjing University of Science and Technology in China designed worm-like aramid nanofibers (ANF) into rod-like microstructures, and then self-assembled with Ti3C2Tx to form a layered solid structure. An ultra-thin, ultra-strong, ultra-soft and thermally stable film. The rigid symmetrical aromatic ring of rod-shaped ANF is completely straightened and is well stacked in the skeleton into a crystalline form, so that the rod-shaped ANF can enhance the network structure and effectively dissipate energy, thereby generating metal-like mechanical properties, that is, unprecedented tensile strength (300.5 MPa), high Young's modulus (13.6 GPa) and excellent folding resistance (>10000 times). More importantly, this MXene/ANF composite film has excellent EMI shielding effect (8814.5 dB cm2 g –1), and the flame retardancy can be in the temperature range of 100°C (355 MPa) to 300°C (136 MPa) Extensive operations are performed internally to eliminate >99% of electromagnetic waves; this guarantees its potential EMI shielding application under certain extreme conditions. Related work was published in the famous journal "ACS Appl. Mater.Interfaces" with the title of "Metal-Level Robust, Folding Endurance, and Highly Temperature-Stable MXene-Based Film with Engineered Aramid Nanofiber for Extreme-Condition Electromagnetic Interference Shielding Applications".
Paper link:
https://pubs.acs.org/doi/10.1021/acsami.0c07387