New tech delivers high-tech film that blocks electromagnetic interference

Electromagnetic interference (EMI), which can harm smartphones, tablets, chips, drones, wearables, and even aircraft and human health, is increasing with the explosive proliferation of devices that generate it. The market for EM-blocking solutions, which employ conductive or magnetic materials, is expected to surpass $7 billion by 2022.

Andre Taylor, associate professor of chemical and biomolecular engineering at the NYU Tandon School of Engineering, along with a team that included Yury Gogotsi, Distinguished University and Charles T. and Ruth M. Bach Professor Materials Science and Engineering at Drexel University, and Menachem Elimelech, Roberto C. Goizueta Professor of Chemical & Environmental Engineering at Yale University used an innovative technique to produce relatively low-cost EMI-blocking composite films.

The study, "Layer-by-Layer Assembly of Cross-Functional Semi-transparent MXene-Carbon Nanotubes Composite Films for Next-Generation Electromagnetic Interference Shielding," appears in the October 31, 2018 issue of Advanced Functional Materials. Lead authors include Guo-Ming Weng, a post-doctoral fellow at NYU Tandon, and Jinyang Li, associate professor of materials science and engineering at Southwest Jiaotong University, Chengdu, China.

To fashion the films, the team employed spin-spray layer-by-layer processing (SSLbL), a method Taylor pioneered in 2012. The system employs mounted spray heads above a spin coater that deposit sequential nanometer-thick monolayers of oppositely charged compounds on a component,producinghigh quality films in much less time than by traditional methods, such as dip coating.

The process allowed them to fashion flexible, semi-transparent EMI-shielding film comprising hundreds of alternating layers of carbon nanotube (CNT), an oppositely charged titanium carbide called MXene—a family of carbide flakes first engineered by Gogotsi—and polyelectrolytes. Taylor explained that those charge characteristics confer benefits beyond EMI shielding.