Lightweight and flexible electrospun polymer nanofiber/metal nanoparticle hybrid membrane for high-performance electromagnetic interference shielding

To resist the increasingly serious radiation pollution, there is a great need for the fabrication of high-performance electromagnetic interference (EMI) shielding materials. However, it is a great challenge to prepare EMI shielding materials with high efficiency, lightweight, and flexibility for practical applications. Here, we demonstrate an efficient and facile approach to prepare freestanding, lightweight, and flexible crosslinking polyacrylonitrile (CPAN) nanofiber (NF)/metal nanoparticle (MNP) hybrid membranes with a high efficiency and reasonable strength via electrospinning followed by an electroless deposition process. In contrast to a Cu- and Ni-decorated CPAN NF membrane, the resultant CPAN NF/Ag nanoparticle (NP) hybrid membrane exhibited much better electrical conductivity. Furthermore, a superior EMI shielding effectiveness of ≈90 dB is achieved for the lightweight CPAN NF/Ag NP hybrid membrane (53 µm), which is superior to pure metal and most of the synthesized EMI shielding materials. The excellent EMI shielding efficiency is attributed to the high conductivity of MNPs and favorable porous structure in the hybrid NF membrane. In addition, the resultant CPAN NF/MNP hybrid membrane shows a reasonable mechanical strength and excellent flexibility. The prepared polymer NF/MNP hybrid membrane shows promising applications in smart portable and wearable electronics. A porous, lightweight membrane containing nanostructured polymers and metals can block more than 99.999999% of stray radio frequency radiation. Smartphones and other communication devices normally contain an internal wrapping layer of rigid metal designed to reflect and absorb unwanted electromagnetic signals. Xiaofeng Lu and Ce Wang from Jilin University in Changchun City, China, have now developed a shielding material that can be bent and folded thousands of times for applications including wearable electronics. The team spun nanoscale-thin fibers of polyacrylonitrile into a membrane, and then used electrical deposition techniques to coat the polymer with silver, copper, or nickel nanoparticles. This approach produced flexible and highly conductive materials containing multiple pore spaces that reflect electromagnetic noise. The membrane's shielding efficiency surpassed that of pure silver or aluminum foils, even after multiple mechanical deformations. Freestanding, lightweight, and flexible crosslinking polyacrylonitrile (CPAN) nanofiber (NF)/metal nanoparticles (MNPs) hybrid membrane is used as high-performance electromagnetic interference (EMI) shielding material. A superior EMI shielding effectiveness with a small thickness of several tens of micrometers is achieved.