Low-Cost Method for Metal Nano-Coating of Anisotropic Fibers

Physical Sciences, Inc. (PSI) proposes to demonstrate the low cost fabrication of chopped carbon fibers with a 50 nm thick, continuous copper coating deposited by electroless methods. We will utilize electrospinning to fabricate uniform polyacrylonitrile fibers with a diameter that upon pyrolysis will yield carbon fibers with 2 micron diameter. The polymer fibers will be pyrolyzed under tension to yield straight carbon fibers. These continuous fibers will be chopped to provide lengths of from 3 to 6 mm, for the 2 micron fibers. Because the fibers are straight, they will be relatively easy to disperse. The copper coated anisotropic carbon fibers are expected to have an extinction coefficient exceeding 6 m^2/g at 35 GHz. During the Phase I Option, PSI will fabricate 1 micron diameter, copper coated fibers. The Phase II program will enable diameter, aspect ratio and electrical conductivity tuning and process scale-up to the kg level. Our expertise with electrospinning scale-up to produce 5 km long tows of 3 micron polymer fiber enables a solid baseline production to build upon in Phase II.