Nanosheets, Nanotubes and Nanowires

Semiconducting nanowires have been made from conventional semiconducting materials, such as gallium arsenide and also from less conventional materials [84]. 

In both cases, the nanotubes had lengths on the order of tens of micrometres. 

Such tubes are expected to be useful as model systems for the study of protein channel transport phenomena, and may find application in the controlled release of chemical substances. Buckyball fullerene spheres have also been made that are capable of holding and releasing a single molecule of water or other material [89]. 

16 Emerging Areas in Emulsions, Foams, Suspensions and Aerosols 

Nanotubes can also be filled with a variety of other molecules to create nanometre-scale filters. These filters can be used to remove bacteria and viruses from water including the poliovirus, which is less than 30 nm in diameter [93, 94]. Nanotube filters made from carbon have the disadvantage of being more brittle, but have the advantage of being much more heat-resistant (they can be autoclaved) when compared with conventional polymer or cellulose filters [93]. In addition to water purification, nanotube filters can be used to separate components from mixtures of organic compounds [93]. 

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