Flexible, mechanically resilient carbon nanotube composite films for high-efficiency electromagnetic interference shielding

Electromagnetic interference (EMI) originated from radio stations to various electronic appliances and devices is an increasingly serious problem, and there are significant interests in the development of light-weight, high-efficiency materials for EMI shielding. Herein we report novel carbon nanotube (CNT) composite films synthesized by a simple spray and vacuum-filtration method. The film containing 30 wt% single-walled CNTs demonstrates high electrical conductivity up to 20,000 S/m and excellent EMI shielding effectiveness 65 dB, with ∼130 μm in thicknesses and 0.011 g/cm2 in areal density. The composite films are stiffer, stronger and more ductile than neat MWCNT film, i.e. 17.4 versus 3.3 MPa in tensile strength. Our films are sufficiently smooth, tough and flexible, which allow themselves to attach onto any complex curved surface. SWCNTs play an essential role in achieving such exceptional functional and mechanical performance; both SWCNTS and MWCNTS need to be well disentangled prior to the filtration. The composite films would have a wide range of engineering applications, i.e. production of conventional composite laminates due to their porous structure.