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 Breaking bad metals with neutrons
16.01.2018 | DOE/Argonne National Laboratory

nachricht White graphene makes ceramics multifunctional
16.01.2018 | 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: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

Im Focus: A thermometer for the oceans

Measurement of noble gases in Antarctic ice cores

The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

White graphene makes ceramics multifunctional

16.01.2018 | Materials Sciences

Breaking bad metals with neutrons

16.01.2018 | Materials Sciences

ISFH-CalTeC is “designated test centre” for the confirmation of solar cell world records

16.01.2018 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>