'Sticky nanotubes' hold key to future technologies

Pipes and Zalamea, meanwhile, had already been developing theoretical models to describe how the nanotubes would peel away from a surface and from each other. The four researchers then worked together with the others to fine tune the model, which describes the physics of why nanotubes peel off unevenly.

The nanotubes used in the research had a length of about 6 microns, or millionths of a meter, and were 40 nanometers wide, roughly 500 times thinner than a human hair.

The researchers used an atomic force microscope to measure the peeling forces. The nanotube was attached to the end of a diving-board shaped part of the microscope called a microcantilever. As the nanotube was pulled away from a surface, the cantilever bent. This bending movement was tracked with a laser, revealing the forces required to peel the nanotube.

The carbon nanotubes for the research were provided by NASA. With the assistance of Stach, the structure of the nanotubes was characterized using a transmission electron microscope. The research was funded by the National Science Foundation and the Korean Center for Nanomanufacturing and Mechatronics. Strus' work is supported in part with a Bilsland Fellowship, which he was awarded this year.

Future work may focus on making measurements that apply to nanocomposites.

Related Web sites:

Arvind Raman: https://engineering.purdue.edu/ME/People/ptProfile?id=12884

Birck Nanotechnology Center: http://www.nano.purdue.edu

IMAGE CAPTION:

This composite image taken with an electron microscope shows a side and bottom image of a nanotube attached to a "microcantilever," a component in atomic force microscopes. Researchers at Purdue used the experimental setup to precisely measure the forces required to peel nanotubes off of other materials, opening up the possibility of creating standards for nano-manufacturing and harnessing a gecko's ability to walk up walls. The nanotube in this image has a length of about 6 microns, or millionths of a meter, and is 40 nanometers wide, roughly 500 times thinner than a human hair. This image also shows an artistic representation of how a nanotube peels away from surfaces. (Birck Nanotechnology Center, Purdue University)

A publication-quality photo is available at http://news.uns.purdue.edu/images/+2008/raman-sticky.jpg

Abstract on the research in this release is available at: http://news.uns.purdue.edu/x/2008a/080428RamanSticky.html