Featured Research

from universities, journals, and other organizations

Engineering researchers simplify process to make world's tiniest wires

Date:
July 22, 2010
Source:
University of Florida
Summary:
Surface tension isn't a very powerful force, but it matters for small things -- water bugs, paint, and, it turns out, nanowires.

Top: Clumps of extremely tiny nanowires in this image are captured with the aid of an electron microscope. The clumping pattern, which occurs as a result of surface tension during the manufacturing process, limits the usefulness of the wires, which are viewed as a likely core element of more powerful microelectronics, solar cells, batteries and medical tools. Bottom: In this image captured with the aid of an electron microscope, nanowires stand straight up as a result of a new process developed by University of Florida chemical engineering researchers. The engineers apply an electrical charge to the nanostructure during the manufacturing process, charging each wire and making it repel its neighbor, counteracting the opposite force induced by the surface tension. The researchers say the process is inexpensive and simple, a step toward making the nanowires a more common constituent of electronics, medical devices and solar cells.
Credit: Image courtesy of University of Florida

Surface tension isn't a very powerful force, but it matters for small things -- water bugs, paint, and, it turns out, nanowires.

Nanowires are so tiny that a human hair would dwarf them -- some have diameters 150 billionths of a meter. Because of their small size, surface tension that occurs during the manufacturing process pulls them together, limiting their usefulness. This is a problem because the wires are seen as a potential core element of new and more powerful microelectronics, solar cells, batteries and medical tools.

But in a paper in the journal ACS Applied Materials & Interfaces now online, a University of Florida engineering researcher says he has found an inexpensive solution.

Kirk Ziegler, an assistant professor of chemical engineering, said nanowires are most often made today with a process that involves the immersion of the wires.

When complete, each wire is supposed to poke up right next to the other from a flat surface, like bristles on a Lilliputian toothbrush. But Ziegler said the wires are so tiny and so flexible that surface tension clumps them up when dried.

Manufacturers use extremely high pressure to reduce the surface tension, but Ziegler said that process is difficult, expensive and not conducive to large-scale production.

Ziegler and Justin Hill, who will graduate from UF with a doctorate in chemical engineering this summer, realized that they needed to introduce a force that counteracted that of the surface tension. They came up with a process simple enough to be achievable with a nine-volt battery. The researchers apply an electrical charge to the nanostructures during the manufacturing process, charging each tiny wire and making it repel its neighbor.

"As the two nanowires pull toward each other because of the surface tension, the like charges at the tips act to push them apart," Ziegler said. "The aim is to get a net zero force on the structure, so the nanowires stand straight."

Tests of microscope-slide-sized surfaces, each containing trillions of nanowires, showed that the procedure effectively prevents clumping, Ziegler said.

Nanowires have not found wide commercial applications to date, but Ziegler said that as engineers learn how to make and manipulate them, they could underpin far more efficient solar cells and batteries because they provide more surface area and better electrical properties.

"Being able to pack in a higher density of nanowires gives you a much higher surface area, so you start to generate higher energy density," he said.

Ziegler said that biomedical engineers are also interested in using the wires to help deliver drugs to individual cells, or to hinder or encourage individual cell growth. The University of Florida has applied for a patent on the process, he added.


Story Source:

The above story is based on materials provided by University of Florida. The original article was written by Aaron Hoover. Note: Materials may be edited for content and length.


Journal Reference:

  1. Justin J. Hill, Kelly Haller, Brittany Gelfand and Kirk J. Ziegler. Eliminating Capillary Coalescence of Nanowire Arrays with Applied Electric Fields. ACS Applied Materials & Interfaces, 2010; [link]

Cite This Page:

University of Florida. "Engineering researchers simplify process to make world's tiniest wires." ScienceDaily. ScienceDaily, 22 July 2010. <www.sciencedaily.com/releases/2010/07/100721112242.htm>.
University of Florida. (2010, July 22). Engineering researchers simplify process to make world's tiniest wires. ScienceDaily. Retrieved July 22, 2014 from www.sciencedaily.com/releases/2010/07/100721112242.htm
University of Florida. "Engineering researchers simplify process to make world's tiniest wires." ScienceDaily. www.sciencedaily.com/releases/2010/07/100721112242.htm (accessed July 22, 2014).

Share This




More Matter & Energy News

Tuesday, July 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Government Approves East Coast Oil Exploration

Government Approves East Coast Oil Exploration

AP (July 18, 2014) The Obama administration approved the use of sonic cannons to discover deposits under the ocean floor by shooting sound waves 100 times louder than a jet engine through waters shared by endangered whales and turtles. (July 18) Video provided by AP
Powered by NewsLook.com
Sunken German U-Boat Clearly Visible For First Time

Sunken German U-Boat Clearly Visible For First Time

Newsy (July 18, 2014) The wreckage of the German submarine U-166 has become clearly visible for the first time since it was discovered in 2001. Video provided by Newsy
Powered by NewsLook.com
Obama: U.S. Must Have "smartest Airports, Best Power Grid"

Obama: U.S. Must Have "smartest Airports, Best Power Grid"

Reuters - US Online Video (July 17, 2014) President Barak Obama stopped by at a lunch counter in Delaware before making remarks about boosting the nation's infrastructure. Mana Rabiee reports. Video provided by Reuters
Powered by NewsLook.com
Crude Oil Prices Bounce Back After Falling Below $100 a Barrel

Crude Oil Prices Bounce Back After Falling Below $100 a Barrel

TheStreet (July 16, 2014) Oil Futures are bouncing back after tumbling below $100 a barrel for the first time since May yesterday. Jeff Grossman is the president of BRG Brokerage and trades at the NYMEX. Grossman tells TheStreet the Middle East is always a concern for oil traders. Oil prices were pushed down in recent weeks on Libya increasing its production. Supply disruptions in Iraq fading also contributed to prices falling. News from China's economic front showing a growth for the second quarter also calmed fears on its slowdown. Jeff Grossman talks to TheStreet's Susannah Lee on this and more on the Energy Department's Energy Information Administration (EIA) report. Video provided by TheStreet
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins