Carbon Nanotubes Get Functionalized Without Losing Key Characteristics

Carbon nanotubes (CNTs) possess characteristics that have tantalized researchers for decades with their extraordinary electrical conductivity.

But in many applications it hardly seemed to matter because CNTs have remained insoluble, making them impossible to disperse in a liquid for coating applications. Instead of dispersing in the liquid the CNTs would just lump together.

Researchers have known for some time that functionalizing CNTs in such a way that they don’t lump together is the way forward, but the problem has been once you functionalize CNTs for that purpose they lose their conductive and luminescent capabilities that made them so attractive in the first place.

But research out of the University of Maryland may have made a breakthrough in this area.

The researchers have found a way through wet chemistry, in a process known as Billups-Birch reductive alkylcarboxylation, to introduce a defect into CNTs that keeps them from lumping together but doesn’t prevent them from retaining their conductivity along certain parts of the CNT.

The research, which was just published in the journal Nature Communicationsand led by Assistant Professor Yu Huang Wang of the Department of Chemistry and Biochemistry, is targeted for battery applications and luminescent biosensors. For those interested a seven-page PDF file on the Nature research can be downloaded here. 

"This is important for the future use of these materials in batteries and solar cells where efficient charge collection and transport are sought," Wang explains. "These CNTs also could be used as highly sensitive biochemical sensors because of their sharp optical absorption and long-lived fluorescence in the near infrared regions where tissues are nearly optically transparent."

Interestingly the research claims to be the first wet chemistry process for producing “clustered functional groups at a controlled, constant propagation rate” with carbon nanotubes.