Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Chemists get custom-designed microscopic particles to self-assemble in liquid crystal

26.11.2009
Chemists and physicists have succeeded in getting custom-shaped microparticles to interact and self-assemble in a controlled way in a liquid crystal.
The research, federally funded by the National Science Foundation, appears in the Nov. 20 edition of the journal Science.

"We're learning the rules about how these lithographic particles self-assemble," said Thomas G. Mason, a UCLA professor of chemistry and physics and a member of the California NanoSystems Institute at UCLA. "This method may enable us to cause them to assemble in desired configurations."

The scientists anticipate that their "LithoParticles," which are made of solid polymeric materials, will have significant technological and scientific uses.

"We're examining how pairs of particles interact and come to attach together," Mason said. "If we can get the particles to interact in certain controlled ways, we can build larger-scale assemblies that may have applications in photonics, optical communication networks and a variety of other areas."

Mason and his colleagues — lead author Clayton Lapointe, a postdoctoral scholar at UCLA, formerly at the University of Colorado at Boulder, and Ivan Smalyukh, an assistant professor of physics at the University of Colorado at Boulder — used an optical microscope to study the attractions between the particles, which they custom designed in various shapes, including triangles, squares and pentagons. The particles are too small to see with the unaided eye but are quite clear with the instrument.

"This is a very complex material that we have created," said Mason, whose research is at the intersection of chemistry, physics, engineering and biology. "We have made lithographic particles dispersed in a liquid crystal, and the molecular constituents are aligned."

Particles of different shapes interact in different ways, Lapointe, Mason and Smalyukh report. Those with an odd number of sides, such as triangles and pentagons, interact differently than particles shaped like squares.

"In this environment, the particles have different kinds of interactions that depend on their shapes," Mason said. "We have shown in a systematic way how by changing the number of sides of the particles in a controlled way, we can characterize the differences in their interactions."

The scientists added materials to the liquid crystal to get the particles to attract. They produced the geometric particles using the same method Mason and his UCLA used to design and mass-produce billions of fluorescent microscale particles in the shapes of all 26 letters of the alphabet, as well as geometric shapes, such as triangles, crosses and doughnuts, in 2007. Now they have watched the particles interact.

In another paper, UCLA postdoctoral scholar Kun Zhao and Mason report discovering new states of matter in two dimensions. Their research, which appears in the Nov. 13 edition of the journal Physical Review Letters, focused on a two-dimensional surface with pentagon-shaped particles that were free to move on this surface. Zhao and Mason studied the structures as they increased the area fraction of the pentagons in the confined two-dimensional plane. They used a lithographic technique to make the particles and studied them in water on a flat glass surface.

UCLA is California's largest university, with an enrollment of nearly 38,000 undergraduate and graduate students. The UCLA College of Letters and Science and the university's 11 professional schools feature renowned faculty and offer more than 323 degree programs and majors. UCLA is a national and international leader in the breadth and quality of its academic, research, health care, cultural, continuing education and athletic programs. Five alumni and five faculty have been awarded the Nobel Prize.

Stuart Wolpert | EurekAlert!
Further information:
http://www.chem.ucla.edu/dept/Faculty/Mason
http://www.ucla.edu

More articles from Life Sciences:

nachricht Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden

nachricht The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: The pyrenoid is a carbon-fixing liquid droplet

Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.

A warming planet

Im Focus: Highly precise wiring in the Cerebral Cortex

Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.

The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Rainbow colors reveal cell history: Uncovering β-cell heterogeneity

22.09.2017 | Life Sciences

Penn first in world to treat patient with new radiation technology

22.09.2017 | Medical Engineering

Calculating quietness

22.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>