Featured Research

from universities, journals, and other organizations

Triblock spheres provide a simple path to complex structures

Date:
January 19, 2011
Source:
University of Illinois at Urbana-Champaign
Summary:
Materials scientists have developed a simple, generalizable technique to fabricate complex structures that assemble themselves. The researchers demonstrated that they can produce a large, complex structure -- an intricate lattice -- from tiny colloidal particles called triblock Janus spheres. Further exploration of triblock spheres and other Janus particles could open doors to a broad area of self-assembly of complex structures from simple materials.

Illinois researchers, from left, doctoral student Qian Chen, research scientist Sung Chul Bae and Steve Granick, professor of materials science and engineering and of physics, developed tiny, simple spheres that self-assemble into intricate structures, such as a lattice that could function as a filter.
Credit: L. Brian Stauffer

University of Illinois materials scientists have developed a simple, generalizable technique to fabricate complex structures that assemble themselves.

Their advance, published in the Jan. 20 issue of Nature, utilizes a new class of self-assembling materials that they developed. The team demonstrated that they can produce a large, complex structure -- an intricate lattice -- from tiny colloidal particles called triblock Janus spheres.

"This is a big step forward in showing how to make non-trivial, non-obvious structures from a very simple thing," said Steve Granick, Founder Professor of Engineering at the University of Illinois and a professor of materials science and engineering, chemistry, and physics. "People know a lot about how to do it with molecules -- soaps for example -- but scientists and engineers know very little about how to make it happen with particles. Particles are very different from molecules: They're big, they're nonflexible, and they have lots of critically different materials properties."

Much of the work to date in making complicated structures from colloidal particles has been done through computer simulation. Researchers model complicated designs built of highly complicated particles.

However, creating complicated building blocks for experimental use is difficult. By contrast, the triblock Janus spheres' elegant simplicity makes them ideal for real-world manufacture.

"It was conceptually challenging to fabricate a complex porous material from a simple design, especially in the field of colloidal particles," said graduate student Qian Chen, a co-author of the paper. "Here, we achieve that with really easy designs that we can use in experiments."

Granick's group is well-known for its work with Janus particles. Named for the dual-natured Roman god, Janus particles have two sides or segments of different surface chemistry. Having explored spheres with two different-natured halves, Chen had the idea to make spheres with three "stripes" of reactivity, dubbed triblock Janus spheres. The center band is charged, while the poles are hydrophobic, or water-adverse.

"After many experiments with Janus particles, I wanted to see if adding one more segment would introduce more surprises," Chen said. "Usually in colloid science people use particles that have a uniform surface chemistry. But for this particle, it's like a block polymer. It has three segments of chemistry."

In a salt-water solution, the hydrophobic poles are drawn together, while the charged equators repel one another. As a result, the spheres form a complex lattice where only the poles are in contact with one another. The hydrophobic polar caps are large enough to come into contact with two other spheres. This causes the spheres to arrange into a formation like a six-pointed star, creating a sheet of delicate lace.

Such porous sheets of schizoid particles, hydrophobic and hydrophilic at the same time, could have applications as specialized filters.

"It's like a better soap," Granick said. "Just as soap is very good at dissolving both fats and water-soluble things, our new lacy lattice can also filter out both water-soluble and oil-soluble matter. We have this wonderful self-produced lacy structure that's oil-loving and water-loving at different parts in a periodic array."

The team could apply their simple particle design to fabricate other planar laces. Adjusting the size of the spheres or the proportion of the bands could lead to other lattice patterns or tuned pore sizes. In addition, further exploration of triblock spheres and other Janus particles could open doors to a broad area of self-assembly of complex structures from simple materials.

"Someday maybe we could have a soup of different components, remove some of it, and there would be a microelectronic chip," Granick said. "It's a brand new area. The materials are so different that the structures that they form will be different."


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.


Journal Reference:

  1. Qian Chen, Sung Chul Bae, Steve Granick. Directed self-assembly of a colloidal kagome lattice. Nature, 2011; 469 (7330): 381 DOI: 10.1038/nature09713

Cite This Page:

University of Illinois at Urbana-Champaign. "Triblock spheres provide a simple path to complex structures." ScienceDaily. ScienceDaily, 19 January 2011. <www.sciencedaily.com/releases/2011/01/110119141733.htm>.
University of Illinois at Urbana-Champaign. (2011, January 19). Triblock spheres provide a simple path to complex structures. ScienceDaily. Retrieved September 16, 2014 from www.sciencedaily.com/releases/2011/01/110119141733.htm
University of Illinois at Urbana-Champaign. "Triblock spheres provide a simple path to complex structures." ScienceDaily. www.sciencedaily.com/releases/2011/01/110119141733.htm (accessed September 16, 2014).

Share This



More Health & Medicine News

Tuesday, September 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

President To Send 3,000 Military Personnel To Fight Ebola

President To Send 3,000 Military Personnel To Fight Ebola

Newsy (Sep. 16, 2014) President Obama is expected to send 3,000 troops to West Africa as part of the effort to contain Ebola's spread. Video provided by Newsy
Powered by NewsLook.com
Man Floats for 31 Hours in Gulf Waters

Man Floats for 31 Hours in Gulf Waters

AP (Sep. 16, 2014) A Texas man is lucky to be alive after he and three others floated for more than a day in the Gulf of Mexico when their boat sank during a fishing trip. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Ivorians Abandon Monkey Pets in Fear Over Ebola Virus

Ivorians Abandon Monkey Pets in Fear Over Ebola Virus

AFP (Sep. 16, 2014) Since the arrival of Ebola in Ivory Coast, Ivorians have been abandoning their pets, particularly monkeys, in the fear that they may transmit the virus. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com
Study Links Male-Pattern Baldness To Prostate Cancer

Study Links Male-Pattern Baldness To Prostate Cancer

Newsy (Sep. 16, 2014) New findings suggest men with a certain type of baldness at age 45 are 39 percent more likely to develop aggressive prostate cancer. Video provided by Newsy
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