Large-Scale Nanofiber Manufacturing| High-Performance Multifunctional Nanopapers withSuperior Mechanical Strength, Electromagnetic InterferenceShielding, and Thermal Management for Next-GenerationElectronics

Professor Zeng Jinsong from South China University of Technology AFM: High-Performance Multifunctional Nanopapers with Superior Mechanical Strength, Electromagnetic Interference Shielding, and Thermal Management for Next-Generation Electronics

With the rapid development of 5G industry and the advent of the AI era, the fast-growing market of electronic and electrical devices has led to overcrowded high-frequency electromagnetic waves in space, which can interfere with different communication channels. Moreover, electromagnetic radiation from highly integrated circuits may not only cause malfunctions in nearby devices but also disrupt the normal operation of the devices themselves. Therefore, electromagnetic radiation has become a significant challenge in many fields including electronics, communications, military, and medical equipment. Consequently, the importance of high-performance electromagnetic shielding materials is increasing. Modern electronic devices particularly require lightweight, flexible, efficient, high-temperature resistant shielding materials with excellent mechanical properties, which should minimize space occupation while maintaining normal flexible functionalities.

In this context, Professor Zeng Jinsong's team at South China University of Technology has developed an ultra-high-performance flexible electromagnetic shielding nanopaper. This material features a "sandwich" structure consisting of a core layer providing mechanical strength and surface layers offering electromagnetic shielding capability. The main materials for the core and surface layers are high-strength aramid nanofibers (ANFs) and highly conductive silver nanowires (AgNWs), respectively. Additionally, MXenes modified with nanocellulose (CM9) were used to enhance the mechanical strength of the core layer and the conductivity of the surface layer. This achievement was published in Advanced Functional Materials under the title "High-Performance Multifunctional Nanopapers with Superior Mechanical Strength, Electromagnetic Interference Shielding, and Thermal Management for Next-Generation Electronics".

Fig.1 Preparation method of flexible EMI shielding nanopaper

In this nanopaper material, CM9 forms a nacre-mimetic "brick-and-mortar" microstructure with both ANFs and AgNWs, endowing the material with superior mechanical properties. Moreover, CM9 in the AgNWs conductive network further improves its conductivity. The resulting nanopaper exhibits tensile strength exceeding 700 MPa, toughness over 100 MJ/m3, and overall conductivity surpassing 1000 S/cm. 

Fig.2 Mechanical performance characterization

Benefiting from its excellent conductivity, the nanopaper achieves electromagnetic interference shielding effectiveness above 60 dB, reaching up to 105 dB - capable of blocking over 99.99999999% of electromagnetic radiation, meeting military standards. The nanopaper also demonstrates outstanding mechanical stability, maintaining over 400 MPa tensile strength and above 50 dB shielding effectiveness even after hundreds of thousands of folding cycles.

Fig.3 EMI shielding capability characterization

Beyond electromagnetic shielding, the nanopaper's excellent conductivity enables remarkable photothermal and electrothermal conversion capabilities, achieving stable heating up to 240°C. Due to its exceptional mechanical stability, the nanopaper maintains stable electrothermal performance even when folded into origami boats, capable of melting ice and even bringing water to boiling.

Fig.4 Thermal management performance of flexible EMI shielding nanopaper

Original article: https://doi.org/10.1002/adfm.202418899