Featured Research

from universities, journals, and other organizations

Polarized Particles Join Toolbox For Building Unique Structures

Date:
October 17, 2006
Source:
University of Illinois at Urbana-Champaign
Summary:
Researchers at the University of Illinois at Urbana-Champaign have created polarized, spherical particles that spontaneously self-assemble into clusters with specific shapes and distributions of electric charge. The polarized particles can be used in the directional self-assembly of intricate shapes and unique structures.

Steve Granick, a professor of materials science and engineering, of chemistry and of physics, above, and Erik Luijten, a professor of mateials science and engineering, have created polarized, spherical particles that spontaneously self-assemble into clusters with specific shapes and distributions of electric charge.
Credit: Image courtesy of University of Illinois at Urbana-Champaign

Researchers at the University of Illinois at Urbana-Champaign have created polarized, spherical particles that spontaneously self-assemble into clusters with specific shapes and distributions of electric charge. The polarized particles can be used in the directional self-assembly of intricate shapes and unique structures.

"The world abounds with particles that have traditionally been treated as geometrically symmetric, chemically isotropic and electrically uniform," said Steve Granick, a professor of materials science and engineering, chemistry and physics. "We have muddied the waters a bit by asking: 'What happens when we build clusters from particles that have an uneven distribution of electric charge?' "

The polarized spheres are called Janus particles; Janus was the Roman god of change, often portrayed with two faces gazing in opposite directions. The spheres offer new opportunities in particle engineering for building particular structures. The clusters may also prove useful as simple systems in which to explore the role of charge interactions in determining how proteins aggregate.

Granick and his collaborators describe their work in a paper accepted for publication in the journal Nano Letters, and posted on its Web site.

To make their Janus particles, the researchers begin with negatively charged beads one micron in diameter. Using electron beam deposition, they coat one hemisphere of the beads with a gold film, which is then made positively charged.

When placed in solution, the particles spontaneously self-assemble into specific geometrical shapes depending on the number of particles. For example, clusters of seven particles resemble a flywheel, which can revolve around a polar axle.

The compact shapes differ fundamentally from the strings and rings formed by magnetic particles, said Granick, who also is a researcher at the Frederick Seitz Materials Research Laboratory and at the Beckman Institute for Advanced Science and Technology.

"The observed shapes are in excellent agreement with computer simulations," said Erik Luijten, a professor of materials science and engineering, and a corresponding author of the paper. "The simulations not only show you the shapes, they also show you how the particles are oriented in the cluster."

Surprisingly, the charge distribution of the initial Janus particles is preserved in the clusters. One half of each cluster tends to be positively charged; the other half negatively charged. This uneven distribution of surface charge could be utilized, perhaps, in the directional self-assembly of particles into more elaborate and intricate shapes.

"Future work could consider particles whose shape is not just spherical, but also rod-like or oblate," Granick said. "This is just the beginning of something that will catch a lot of people's imaginations."

Lead authors of the paper were graduate student Liang Hong and postdoctoral research associate Angelo Cacciuto. The work was funded by the National Science Foundation and the Petroleum Research Fund.


Story Source:

The above story is based on materials provided by University of Illinois at Urbana-Champaign. Note: Materials may be edited for content and length.


Cite This Page:

University of Illinois at Urbana-Champaign. "Polarized Particles Join Toolbox For Building Unique Structures." ScienceDaily. ScienceDaily, 17 October 2006. <www.sciencedaily.com/releases/2006/10/061012184258.htm>.
University of Illinois at Urbana-Champaign. (2006, October 17). Polarized Particles Join Toolbox For Building Unique Structures. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2006/10/061012184258.htm
University of Illinois at Urbana-Champaign. "Polarized Particles Join Toolbox For Building Unique Structures." ScienceDaily. www.sciencedaily.com/releases/2006/10/061012184258.htm (accessed September 17, 2014).

Share This



More Matter & Energy News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Space Race Pits Bezos Vs Musk

Space Race Pits Bezos Vs Musk

Reuters - Business Video Online (Sep. 16, 2014) Amazon CEO Jeff Bezos' startup will team up with Boeing and Lockheed to develop rocket engines as Elon Musk races to have his rockets certified. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
MIT's Robot Cheetah Unleashed — Can Now Run, Jump Freely

MIT's Robot Cheetah Unleashed — Can Now Run, Jump Freely

Newsy (Sep. 16, 2014) MIT developed a robot modeled after a cheetah. It can run up to speeds of 10 mph, though researchers estimate it will eventually reach 30 mph. Video provided by Newsy
Powered by NewsLook.com
Manufacturer Prints 3-D Car In Record Time

Manufacturer Prints 3-D Car In Record Time

Newsy (Sep. 15, 2014) Automobile manufacturer Local Motors created a drivable electric car using a 3-D printer. Printing the body only took 44 hours. Video provided by Newsy
Powered by NewsLook.com
Refurbished New York Subway Tunnel Unveiled After Sandy Damage

Refurbished New York Subway Tunnel Unveiled After Sandy Damage

Reuters - US Online Video (Sep. 15, 2014) New York officials unveil subway tunnels that were refurbished after Superstorm Sandy. Nathan Frandino reports. Video provided by Reuters
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