Forming Chemical Microsensors

The researchers used a form of chemical vapour deposition and lithography to create the readymade 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. 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.

As these ready made ultramicroelecrodes are carbon based they open up new possibilities for use in living systems. The biocompatibility of carbon is in stark contrast with the obvious problems that platinum and other metal based probes can pose for living tissue. The Warwick research team is already beginning to explore how their single walled carbon nanotube based ultramicroelecrodes can be used to measure levels of neurotransmitters.

The new ultramicroelecrodes also open up interesting possibilities for catalysis in fuel cells. Up till now researchers had been aware that this form of carbon nanotubes appeared to be particularly useful in the area of catalysis but there was uncertainty as to whether it was the properties of the carbon nanotubes per se that provide this benefit or whether it was due to impurities in their production. The researchers have been able to use this new method of single walled carbon nanotube assembly to prove that it is actually the properties of the carbon nanotubes themselves that are useful for catalysis. The new carbon nanotube assembly technique brings a further benefit to catalysis applications as the Warwick researchers have been able to use electrodepoistion to apply specific metal coatings to the ready formed single walled carbon nanotube microelectrode networks. This will be of benefit to anyone wanting to use single walled carbon nanotube for catalysis in fuel cell technology.; Source: University of Warwick