Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Tiny ’nanofingers’ to support sensors, other applications

08.12.2003


Sheikh Akbar


Future sensors may take the form of microscopic finger-like structures developed at Ohio State University.

Engineers here have found an easy way to carve the surface of inexpensive ceramic material into tiny filaments, creating a platform for devices that detect chemicals in the air. They could also be used to clean up toxic chemicals or gather solar energy, or to form fog-free or self-cleaning surfaces.

Each filament, or "nanofinger," consists of a single crystal of the compound titanium oxide, and measures up to five micrometers long and at most 50 nanometers wide. A micrometer is one millionth of a meter, and a nanometer is one billionth of a meter.



The new process offers a simple chemical alternative to typical machine-based methods for carving ceramics, explained Sheikh Akbar, professor of materials science and engineering and founding director of the Center for Industrial Sensors and Measurements at Ohio State. Manufacturers often use diamond-edged rotary tools, lasers, or even ultrasound, because ceramics are hard and prone to chipping.

"Machining ceramics isn’t easy," Akbar said. "This might be another way." The patent-pending process is unique, he said, because it carves uniform filaments on a very small scale.

Materials science student Sehoon Yoo discovered the process and is developing it to earn his doctoral degree, with Akbar as his advisor. Kenneth Sandhage, formerly a professor at Ohio State and now at the Georgia Institute of Technology, is also advising Yoo.

Akbar described the process December 8 during the International Conference on Materials for Advanced Technologies meeting in Singapore.

The idea for the project came to Akbar when he attended a chemistry lecture in Japan in 1998. Researchers there had learned how to carve nanometer-sized honeycombs in ceramic. But because the procedure was very complicated, the speaker remarked that it had no practical commercial use.

"I thought, this is a great platform for chemical sensing," Akbar said.

He then set Yoo to work to find a better process for carving honeycombs, and the student discovered how to carve nanofingers instead.

Yoo’s method involves baking the ceramic compound titanium dioxide at high heat inside a cloud of hydrogen gas. The hydrogen reacts with some of the oxygen in the material to create water, and heat binds the atoms of the ceramic together. What’s left is a very dense ceramic minus some oxygen atoms -- its then simply titanium oxide -- covered in a uniform array of nanofingers.

"We’re still not sure exactly how it works," Yoo said. He suspects that somehow the chemical reaction frees atoms of titanium that normally remain bound in the material.

He’s tried the same experiment with other chemical elementsoxides -- tin, cerium, and zirconium -- to no avail, and will soon examine molybdenum and tungsten. But his work with titanium has advanced to the point that he can turn a penny-sized sample of the material into a rudimentary sensor that detects hydrogen.

When a hydrogen atom touches a finger, the finger absorbsreacts with it, and releases an electron. The electron travels down the finger to the base of the material, where the charge can be detected as a sensor signal.

The nanofingers provide a large surface area -- good for capturing chemicals from the air, Akbar said.

That’s why the material would also be good for gathering light for electricity-generating solar cells. Another potential application is photocatalysis, in which light activates chemical reactions that clean contaminants from soil or water. The fingers could be coated with different chemicals for different functions, Akbar said.

"What’s really great about this process is that it involves no fancy techniques. All you need is a furnace and a cylinder of hydrogen," he added.


Contact: Sheikh Akbar, (614) 292-6725; Akbar.1@osu.edu
Sehoon Yoo, (614) 292-7427; Yoo.89@osu.edu

Written by Pam Frost Gorder, (614) 292-9475; Gorder.1@osu.edu

Pam Frost Gorder | OSU
Further information:
http://www.acs.ohio-state.edu/units/research/

More articles from Materials Sciences:

nachricht High-tech sensing illuminates concrete stress testing
20.07.2017 | University of Leeds

nachricht Here's a tip: Indented cement shows unique properties
20.07.2017 | Rice University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

Leipzig HTP-Forum discusses "hydrothermal processes" as a key technology for a biobased economy

12.07.2017 | Event News

 
Latest News

Researchers create new technique for manipulating polarization of terahertz radiation

20.07.2017 | Information Technology

High-tech sensing illuminates concrete stress testing

20.07.2017 | Materials Sciences

First direct observation and measurement of ultra-fast moving vortices in superconductors

20.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>