Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Self-Assembling Structures Open Door To New Class Of Materials

Researchers led by Founder Professor of Engineering Steve Granick, right, have developed tiny spheres that attract water to form "supermolecule" structures. Team members, from left, Qian Chen, doctoral student in materials science and engineering; Sung Chul Bae, research scientist; and Jonathan Whitmer, doctoral student in physics.  Photo by L. Brian Stauffer
Researchers led by Founder Professor of Engineering Steve Granick, right, have developed tiny spheres that attract water to form "supermolecule" structures. Team members, from left, Qian Chen, doctoral student in materials science and engineering; Sung Chul Bae, research scientist; and Jonathan Whitmer, doctoral student in physics. Photo by L. Brian Stauffer

Abstract:
Researchers at the University of Illinois and Northwestern University have demonstrated bio-inspired structures that self-assemble from simple building blocks: spheres.

Self-Assembling Structures Open Door To New Class Of Materials

Champaign, IL | Posted on January 13th, 2011

The helical "supermolecules" are made of tiny colloid balls instead of atoms or molecules. Similar methods could be used to make new materials with the functionality of complex colloidal molecules. The team will publish its findings in the Jan. 14 issue of the journal Science.

"We can now make a whole new class of smart materials, which opens the door to new functionality that we couldn't imagine before," said Steve Granick, Founder Professor of Engineering at the University of Illinois and a professor of materials science and engineering, chemistry, and physics.

Granick's team developed tiny latex spheres, dubbed "Janus spheres," which attract each other in water on one side, but repel each other on the other side. The dual nature is what gives the spheres their ability to form unusual structures, in a similar way to atoms and molecules.

In pure water, the particles disperse completely because their charged sides repel one another. However, when salt is added to the solution, the salt ions soften the repulsion so the spheres can approach sufficiently closely for their hydrophobic ends to attract.

The attraction between those ends draws the spheres together into clusters.

At low salt concentrations, small clusters of only a few particles form. At higher levels, larger clusters form, eventually self-assembling into chains with an intricate helical structure.

"Just like atoms growing into molecules, these particles can grow into supracolloids," Granick said. "Such pathways would be very conventional if we were talking about atoms and molecules reacting with each other chemically, but people haven't realized that particles can behave in this way also."

The team designed spheres with just the right amount of attraction between their hydrophobic halves so that they would stick to one another but still be dynamic enough to allow for motion, rearrangement, and cluster growth.

"The amount of stickiness really does matter a lot. You can end up with something that's disordered, just small clusters, or if the spheres are too sticky, you end up with a globular mess instead of these beautiful structures," said graduate student Jonathan Whitmer, a co-author of the paper.

One of the advantages of the team's supermolecules is that they are large enough to observe in real time using a microscope. The researchers were able to watch the Janus spheres come together and the clusters grow - whether one sphere at a time or by merging with other small clusters - and rearrange into different structural configurations the team calls isomers.

"We design these smart materials to fall into useful shapes that nature wouldn't choose," Granick said.

Surprisingly, theoretical calculations and computer simulations by Erik Luijten, Northwestern University professor of materials science and engineering and of engineering sciences and applied mathematics, and Whitmer, a student in his group, showed that the most common helical structures are not the most energetically favorable. Rather, the spheres come together in a way that is the most kinetically favorable - that is, the first good fit that they encounter.

Next, the researchers hope to continue to explore the colloid properties with a view toward engineering more unnatural structures. Janus particles of differing sizes or shapes could open the door to building other supermolecules and to greater control over their formation.

"These particular particles have preferred structures, but now that we realize the general mechanism, we can apply it to other systems - smaller particles, different interactions - and try to engineer clusters that switch in shape," Granick said.

The team also included University of Illinois graduate students Qian Chen and Shan Jiang and research scientist Sung Chul Bae. The U.S. Department of Energy and the National Science Foundation supported this work.

####

For more information, please click here

Contacts:
Liz Ahlberg
Physical Sciences Editor
217-244-1073

Copyright © University of Illinois at Urbana-Champaign

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Application of air-sensitive semiconductors in nanoelectronics: 2-D semiconductor gallium selenide in encapsulated nanoelectronic devices September 22nd, 2017

Researchers set time limit for ultrafast perovskite solar cells September 22nd, 2017

DNA triggers shape-shifting in hydrogels, opening a new way to make 'soft robots' September 21st, 2017

Physicists develop new recipes for design of fast single-photon gun Physicists develop high-speed single-photon sources for quantum computers of the future September 21st, 2017

Possible Futures

Application of air-sensitive semiconductors in nanoelectronics: 2-D semiconductor gallium selenide in encapsulated nanoelectronic devices September 22nd, 2017

Researchers set time limit for ultrafast perovskite solar cells September 22nd, 2017

DNA triggers shape-shifting in hydrogels, opening a new way to make 'soft robots' September 21st, 2017

Physicists develop new recipes for design of fast single-photon gun Physicists develop high-speed single-photon sources for quantum computers of the future September 21st, 2017

Academic/Education

Two Scientists Receive Grants to Develop New Materials: Chad Mirkin and Monica Olvera de la Cruz recognized by Sherman Fairchild Foundation August 16th, 2017

Moving at the Speed of Light: University of Arizona selected for high-impact, industrial demonstration of new integrated photonic cryogenic datalink for focal plane arrays: Program is major milestone for AIM Photonics August 10th, 2017

Graduate Students from Across the Country Attend Hands-on NanoCamp: Prominent scientists Warren Oliver, Ph.D., and George Pharr, Ph.D., presented a weeklong NanoCamp for hand-picked graduate students across the United States July 26th, 2017

The Physics Department of Imperial College, London, uses the Quorum Q150T to deposit metals and ITO to make plasmonic sensors and electric contact pads July 13th, 2017

Self Assembly

Physicists gain new insights into nanosystems with spherical confinement: Enormous potential for the targeted delivery of pharmaceutical agents and the creation of tailored nanoparticles July 27th, 2017

Oddball enzyme provides easy path to synthetic biomaterials May 17th, 2017

Nanotubes that build themselves April 14th, 2017

Nanocages for gold particles: what is happening inside? March 16th, 2017

Materials/Metamaterials

Copper catalyst yields high efficiency CO2-to-fuels conversion: Berkeley Lab scientists discover critical role of nanoparticle transformation September 20th, 2017

New quantum phenomena in graphene superlattices September 18th, 2017

New insights into nanocrystal growth in liquid: Understanding process that creates complex crystals important for energy applications September 14th, 2017

Corrosion in real time: UCSB researchers get a nanoscale glimpse of crevice and pitting corrosion as it happens September 14th, 2017

Announcements

Application of air-sensitive semiconductors in nanoelectronics: 2-D semiconductor gallium selenide in encapsulated nanoelectronic devices September 22nd, 2017

Researchers set time limit for ultrafast perovskite solar cells September 22nd, 2017

DNA triggers shape-shifting in hydrogels, opening a new way to make 'soft robots' September 21st, 2017

Physicists develop new recipes for design of fast single-photon gun Physicists develop high-speed single-photon sources for quantum computers of the future September 21st, 2017

Research partnerships

GLOBALFOUNDRIES Delivers Custom 14nm FinFET Technology for IBM Systems: Jointly developed 14HP process is world’s only technology that leverages both FinFET and SOI September 20th, 2017

Solar-to-fuel system recycles CO2 to make ethanol and ethylene: Berkeley Lab advance is first demonstration of efficient, light-powered production of fuel via artificial photosynthesis September 19th, 2017

A new approach to ultrafast light pulses: Unusual fluorescent materials could be used for rapid light-based communications systems September 19th, 2017

New insights into nanocrystal growth in liquid: Understanding process that creates complex crystals important for energy applications September 14th, 2017

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project