Recovery Act - Electrokinetic Sorting of Carbon Nanotubes

The use of SWCNTs in new cutting edge devices has the potential to significantly advance technology in areas such as energy, medicine, electronics, and defense, all of which will greatly benefit mankind. However, even though there is a vast commercial potential for products that utilize the unique features of SWCNTs the introduction of these products is limited by the availability of bulk quantities of SWCNTs monodispersed in their unique properties of diameter, bandgap, and or/and electronic type. To address this issue there have been several research efforts with the goal of separating mixtures of SWCNTs into fractions of pure m-and s-SWCNTs using controlled electrical breakdown, dielectrophoresis and chemical moieties that selectively react with either type of nanotube. Although several selective separation methods have been reported, none of these techniques has demonstrated the simultaneous sensitivity, scalability, and effectiveness, so a realistic separation method for high yield and massive quantities with a specific chirality of nanotubes is still an unmet goal. To address this unfulfilled need in the industrial processing of SWCNTs we have developed a unique continuous flow electro-kinetic sorting of SWCNTs combines two innovations. The first part of the process is the isolation of the individual nanotubes from the starting bundle of SWCNTs in a high concentration (2 mg/mL) by using selective non-covalent functionalization (p-p stacking) of SWCNTs through the formation of SWCNTs-conjugated polymer water soluble complex. The second innovation in the process is to couple the output from the chemical separation to a microfluidic based electro-kinetic array that uses different electric field strength and frequency that will enable spatial separation of metallic SWCNT from semiconducting SWCNT. This technique will result in spatially separated fraction of s-SWCNTs and m-SWCNTs with ultrafine and unique optical and physical properties controlled by their geometry (size and chirality). During the Phase I effort we will demonstrate this technology through the development of an integrated 10 chip array breadboard system. With the ability to generate s and m SWCNTs fractions with < 95% monodispersion in length and electronic properties from a high concentration starting solution 2 mg/mL. Commercial Applications and Other Benefits: The commercial driving force for the development of SWNTs sorting technology is to have a large volume of SWNTs that are monodisperese in their electronic type, so they could be directly integrated into a broad range of devices. In 2028, the predicted market for low cost flexible electronics is going to be $300 billion from just 1.6 billion in 2008, and the largest segment will be thin-film transistors (TFT) (in touch screen, e-paper) and memory. Some early CNT sensors, probe tips, and transparent conductive thin films are on the market already with more development to come. For most electronic applications, a single chirality or electronic type, either only metallic or semiconducting SWNTs is highly desirable, thus one of the grand challenges of CNT chemistry has been to separate a nanotube sample into pure fraction.