Researchers measure carbon nanotube i...( LIVERMORE Calif. Carbon nanotubes h...)

LIVERMORE, Calif. Carbon nanotubes have been employed for a variety of uses including composite materials, biosensors, nano-electronic circuits and membranes.

While they have proven useful for these purposes, no one really knows much about whats going on at the molecular level. For example, how do nanotubes and chemical functional groups interact with each other on the atomic scale" Answering this question could lead to improvements in future nano devices.

In a quest to find the answer, researchers for the first time have been able to measure a specific interaction for a single functional group with carbon nanotubes using chemical force microscopy a nanoscale technique that measures interaction forces using tiny spring-like sensors. Functional groups are the smallest specific group of atoms within a molecule that determine the characteristic chemical reactions of that molecule.

A recent report by a team of Lawrence Livermore National Laboratory researchers and colleagues found that the interaction strength does not follow conventional trends of increasing polarity or repelling water. Instead, it depends on the intricate electronic interactions between the nanotube and the functional group.

This work pushes chemical force microscopy into a new territory, said Aleksandr Noy, lead author of the paper that appears in the Oct. 14 online issue of the journal, Nature Nanotechnology.

Understanding the interactions between carbon nanotubes (CNTs) and individual chemical functional groups is necessary for the engineering of future generations of sensors and nano devices that will rely on single-molecule coupling between components. Carbon nanotubes are extremely small, which makes it particularly difficult to measure the adhesion force of an individual molecule at the carbon nanotube surface. In the past, researchers had to rely on modeling, indirect measurements and large microscale tests.

But the Livermore team w
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