Safer Production of Water Dispersible Carbon Nanotubes and Nanotube/Cotton Composite Materials

Abstract

Water-dispersible carbon nanotubes (WD-CNTs) have great importance in the fields of biotechnology, microelectronics, and composite materials. Sidewall functionalization is a popular method of enhancing their dispersibility in a solvent, which is usually achieved by strong acidic treatment. But, treatment under such harsh conditions deviates from green chemistry and degrades the structure and valuable properties of CNTs. Alternative safer and easier plasma method is discussed to produce functionalized CNTs (f-CNTs). The f-CNTs remain dispersed in water for more than 1 month owing to the attachment of a large number of carboxyl groups onto their surfaces. The WD-CNTs are applied to produce conductive cotton textile for the next generation textile technologies. Nonconducting cotton textile becomes electroconductive by repeatedly dipping into the f-CNT-ink and drying in air. The f-CNTs uniformly and strongly cover the individual cotton fibers. After several cycle of dipping into the f-CNT-ink, the textile becomes conductive enough to be used as wire in lighting up an LED. As a demonstration of practical use, the textile is shown as a conductive textile heater, where the textile can produce uniformly up to ca. 80°C within ca. 5 min by applying an electric power of ca. 0.1 W/cm2.