Survival of the Fittest—Nanotubes versus High Power Laser

The Cambridge Spinning Process, invented here at the Department of Materials Science and Metallurgy, uniquely generates textiles composed of aligned, long-length single wall carbon nanotubes (SWCNT), all in one production step.  Impurities, defective CNTs, and less-than-perfect microstructure alignment hamper the textile’s ultimate electrical, thermal, and mechanical properties.

Now, we have developed a laser-based post-process selectively removing defective CNTs and other carbons not forming a threshold thermal pathway. A laser beam rasters across the surface of a partly aligned CNT textile in air. Surviving material is strictly comprised of SWCNTs with a profound and unique improvement in microstructure alignment and crystallinity. Increasing the conductivity 20-fold, the CNT textile’s conductivity is well beyond single-crystal graphite and carbon fiber.

Figure: A laser beam rasters across the surface of a suspended SWCNT textile. Impure carbons burn away leaving behind a thermal conduit of highly aligned and highly crystalline SWCNTs. Scanning electron microscopy show the “before” and “after” microstructure.