Construction, mechanism and prospective of conductive polymer composites with multiple interfaces for electromagnetic interference shielding: A review

The rapid development of modern industry and excessive consumption of petroleum-based polymers have triggered a double crisis presenting a shortage of nonrenewable resources and environmental pollution However, this has provided an opportunity to stimulate researchers to harness native biobased materials for novel advanced materials and applications Nanocellulose-based aerogels, using abundant and sustainable cellulose as raw material, present a third-generation of aerogels that combine traditional aerogels with high porosity and large specific surface area, as well as the excellent properties of cellulose itself Currently, nanocellulose aerogels provide a highly attention-catching platform for a wide range of functional applications in various fields, eg, adsorption, separation, energy storage, thermal insulation, electromagnetic interference shielding, and biomedical applications Here, the preparation methods, modification strategies, composite fabrications, and further applications of nanocellulose aerogels are summarized, with additional discussions regarding the prospects and potential challenges in future development

https://onlinelibrary.wiley.com/doi/pdf/10.1002/adma.202005569

Recent Progress on Nanocellulose Aerogels: Preparation, Modification, Composite Fabrication, Applications

Flexible multifunctional polymer-based electromagnetic interference (EMI) shielding composite films have important application values in the fields of 5G communication technology, wearable electronic devices and artificial intelligence. In this work, Fe3O4/polyamic acid (PAA) nanofiber films are prepared by in-situ polymerization and electrospinning technology, and Ti3C2Tx nanosheets are deposited on the surface of the Fe3O4/PAA nanofiber films via vacuum-assisted filtration. Then, Janus Ti3C2Tx-(Fe3O4/polyimide (PI)) composite films are obtained by thermal imidization. The two sides of the Janus films exhibit completely different properties. The Fe3O4/PI side has excellent hydrophobicity and insulation property, and the Ti3C2Tx side has hydrophilicity and terrific conductivity. When the mass fraction of Ti3C2Tx is 80 wt.%, the Janus Ti3C2Tx-(Fe3O4/PI) composite film has excellent EMI shielding performances and mechanical properties, with EMI shielding effectiveness, tensile strength and Young’s modulus reaching 66 dB, 114.5 MPa and 5.8 GPa, respectively. At the same time, electromagnetic waves show different absorption shielding effectiveness (SEA) when incident from two sides of the Janus films. When the electromagnetic waves are incident from the Fe3O4/PI side, the SEA of the Janus film is 58 dB, much higher than that when the electromagnetic waves are incident from the Ti3C2Tx side (39 dB). In addition, the Ti3C2Tx side of the Janus Ti3C2Tx-(Fe3O4/PI) composite films also has excellent electrothermal and photothermal conversion performances. When the applied voltage is 4 V, the stable surface temperature reaches 108 °C; when it is irradiated by simulated sunlight with power density of 200 mW/cm2, the stable surface temperature reaches 95 °C. 

https://link.springer.com/content/pdf/10.1007/s12274-022-4358-7.pdf

Multifunctional Ti3C2Tx-(Fe3O4/polyimide) composite films with Janus structure for outstanding electromagnetic interference shielding and superior visual thermal management

Cellulose based composite foams and aerogels for advanced energy storage devices

Owing to the development of electronic information technology, the pollution of electromagnetic wave (EMW) radiation is getting worse. Thus, it is urgent to investigate shielding materials with excellent electromagnetic interference (EMI) shielding properties. Recently, electrospinning has been developed in various fields, and one-dimensional nanofibers prepared by electrospinning can realize the shielding of EMW, due to their outstanding advantages. In this review, at the beginning, the basic mechanism of electrospinning technology and related EMI shielding are introduced. Then, different fibrous materials directly from electrospinning for the EMI shielding are summarized. Next, electrospun EMI shielding composites by different post treatments are discussed. Finally, various influencing factors on the EMI shielding properties are summarized. At the end, conclusions and future perspectives are provided. Hopefully, this review would provide basic understanding on the development of electrospun fibrous materials for EMI shielding, and give the future roadmap for the high performance electrospun fiber-based EMI shields.

Electrospun fibrous materials and their applications for electromagnetic interference shielding: A review

Nanocellulose-based porous materials have been recently considered as ideal candidates in various applications. However, challenges on performances remain owing to the disorderly structure and the limited transport specificity. Herein, wood-inspired composite sponges consisting of cellulose nanofibrils (CNFs) and high-aspect-ratio silver nanowires (AgNWs) were generated with anisotropic properties by the directional freeze-drying. The obtained composite sponges exhibited attractive features, such as an excellent compressive stress of 24.5 kPa, low percolation threshold of 0.1 vol % AgNWs, and high electrical conductivity of 1.52 S/cm. Furthermore, the self-assembled ordered structure in the longitudinal direction and synergistic effect between CNFs and AgNWs benefited the sponge interesting anisotropic electrical conductivity, thermal diffusivity, ultrafast electrically induced heating (<5 s), sensitive pressure sensing (errors <0.26%), and electromagnetic interference (EMI) shielding for special practical demands. This multifunctional material inspired by natural woods is expected to broaden new applications as electronic devices for an intelligent switch or EMI shielding.

Yang Li

Papers

Wood-Inspired Anisotropic Cellulose Nanofibril Composite Sponges for Multifunctional Applications.