Carbon Nanocoils for Electromagnetic Wave Absorption Study

Carbon nanocoils(CNCs) had been synthesized in large-scale by pyrolysis of acetylene at 700 ℃ over Fe-Sn nanoparticles derived from chemical vapor deposition. The electromagnetic (EM) wave absorption properties in the gigahertz region (12–110 GHz) of CNCs with a three-dimensional-helical/spiral chiral structure (600~1200 nm coil diameter and 300~500 nm fiber diameter and 500~1500 nm coil pitch) were examined using the open space method. We used two different methods to make EM(Electromagnetic microwave) absorber. It was found that the target value of reflection loss over -20 dB (above 99% absorptivity) necessitated for commercial applications. We obtain the EM absorption composite of 10 wt% addition of CNCs in polydimethyl siloxane (PDMS) for the 18~26,63~75GHz bands by sandwich and 10 wt% addition of CNCs in PDMS for the 56~75GHz bands by ultrasonic vibrating. The thickness of EM absorber are only about 1~1.5mm, and Both have the wideband , high EM absorptivity. The absorption mechanism of the EM wave by CNCs is discussed.