Nanotube production leaps from sooty mess in test tube to ready formed chemical microsensors

Carbon nanotubes’ potential as a super material is blighted by the fact that when first made they often take the form of an unprepossessing pile of sooty black mess in the bottom of a test tube. Now researchers in the University of Warwick’s Department of Chemistry have found a way of producing carbon nanotubes in which they instantly form a highly sensitive ready made electric circuit.

The research has just been published in a paper entitled “Single-Walled Carbon Nanotube Network Ultramicroelectrodes” by University of Warwick researchers Ioana Dumitrescu, Professor Julie Macpherson, Professor Patrick Unwin, and Neil Wilson in Analytical Chemistry, 2008, 10.1021/ac702518g

The researchers used a form of chemical vapour deposition and lithography to create the ready made disc shaped single walled carbon nanotube based ultramicroelectrodes. The nanotubes deposit themselves flat on a surface in a random but relatively even manner. They also all overlap sufficiently to create a single complete metallic micro-circuit right across the final disc. What is even more impressive is that they take up less than one per cent of the surface area of the disc.

This final property makes these instant ultramicroelecrodes particular useful for the creation of ultra sensitive sensors. The low surface area of the conducting part of the disc means that they can be used to screen out background “noise” and cope with low signal to noise ratios making them up to 1000 times more sensitive than conventional ultramicroelecrodes sensors. This property also produces very fast response times allowing them to respond ten times faster than conventional ultramicroelecrodes.