Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button

Home > Press > Penn Researchers Grow Liquid Crystal 'Flowers' That Can Be Used as Lenses

A liquid crystal "flower" under magnification. The black dot at center is the silica bead that generates the flower's pattern.
A liquid crystal "flower" under magnification. The black dot at center is the silica bead that generates the flower's pattern.

Abstract:
A team of material scientists, chemical engineers and physicists from the University of Pennsylvania has made another advance in their effort to use liquid crystals as a medium for assembling structures.

Penn Researchers Grow Liquid Crystal 'Flowers' That Can Be Used as Lenses

Philadelphia, PA | Posted on December 20th, 2013

In their earlier studies, the team produced patterns of "defects," useful disruptions in the repeating patterns found in liquid crystals, in nanoscale grids and rings. The new study adds a more complex pattern out of an even simpler template: a three-dimensional array in the shape of a flower.

And because the petals of this "flower" are made of transparent liquid crystal and radiate out in a circle from a central point, the ensemble resembles a compound eye and can thus be used as a lens.

The team consists of Randall Kamien, professor in the School of Arts and Sciences' Department of Physics and Astronomy; Kathleen Stebe, the School of Engineering and Applied Science's deputy dean for research and professor in Chemical and Biomolecular Engineering and Shu Yang, professor in Engineering's departments of Materials Science and Engineering and Chemical and Biomolecular Engineering. Members of their labs also contributed to the new study, including lead author Daniel Beller, Mohamed Gharbi and Apiradee Honglawan.

Their work was published in Physical Review X.

The researchers' ongoing work with liquid crystals is an example of a growing field of nanotechnology known as "directed assembly," in which scientists and engineers aim to manufacture structures on the smallest scales without having to individually manipulate each component. Rather, they set out precisely defined starting conditions and let the physics and chemistry that govern those components do the rest.

The starting conditions in the researchers previous experiments were templates consisting of tiny posts. In one of their studies, they showed that changing the size, shape or spacing of these posts would result in corresponding changes in the patterns of defects on the surface of the liquid crystal resting on top of them. In another experiment, they showed they could make a "hula hoop" of defects around individual posts, which would then act as a second template for a ring of defects at the surface.

In their latest work, the researchers used a much simpler cue.

"Before we were growing these liquid crystals on something like a trellis, a template with precisely ordered features," Kamien said. "Here, we're just planting a seed."

The seed, in this case, were silica beads — essentially, polished grains of sand. Planted at the top of a pool of liquid crystal flower-like patterns of defects grow around each bead.

The key difference between the template in this experiment and ones in the research team's earlier work was the shape of the interface between the template and the liquid crystal.

In their experiment that generated grid patterns of defects, those patterns stemmed from cues generated by the templates' microposts. Domains of elastic energy originated on the flat tops and edges of these posts and travelled up the liquid crystal's layers, culminating in defects. Using a bead instead of a post, as the researchers did in their latest experiment, makes it so that the interface is no longer flat.

"Not only is the interface at an angle, it's an angle that keeps changing," Kamien said. "The way the liquid crystal responds to that is that it makes these petal-like shapes at smaller and smaller sizes, trying to match the angle of the bead until everything is flat."

Surface tension on the bead also makes it so these petals are arranged in a tiered, convex fashion. And because the liquid crystal can interact with light, the entire assembly can function as a lens, focusing light to a point underneath the bead.

"It's like an insect's compound eye, or the mirrors on the biggest telescopes," said Kamien. "As we learn more about these systems, we're going to be able to make these kinds of lenses to order and use them to direct light."

This type of directed assembly could be useful in making optical switches and in other applications.

The research was supported by the National Science Foundation, Penn's Materials Science Research and Engineering Center and the Simons Foundation.

####

For more information, please click here

Contacts:
Evan Lerner

215-573-6604

Copyright © University of Pennsylvania

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 Links

Download abstract:

Related News Press

News and information

Ultra-flat circuits will have unique properties: Rice University lab studies 2-D hybrids to see how they differ from common electronics July 25th, 2016

Attosecond physics: Mapping electromagnetic waveforms July 25th, 2016

Borrowing from pastry chefs, engineers create nanolayered composites: Method to stack hundreds of nanoscale layers could open new vistas in materials science July 25th, 2016

Integration of novel materials with silicon chips makes new 'smart' devices possible July 25th, 2016

Display technology/LEDs/SS Lighting/OLEDs

Researchers develop faster, precise silica coating process for quantum dot nanorods July 12th, 2016

Integrated trio of 2-D nanomaterials unlocks graphene electronics applications: Voltage-controlled oscillator developed at UC Riverside could be used in thousands of applications from computers to wearable technologies July 7th, 2016

GraphExeter illuminates bright new future for flexible lighting devices June 23rd, 2016

New nanomaterial offers promise in bendable, wearable electronic devices: Electroplated polymer makes transparent, highly conductive, ultrathin film June 13th, 2016

Govt.-Legislation/Regulation/Funding/Policy

Designing climate-friendly concrete, from the nanoscale up: New understanding of concrete’s properties could increase lifetime of the building material, decrease emissions July 25th, 2016

Ultra-flat circuits will have unique properties: Rice University lab studies 2-D hybrids to see how they differ from common electronics July 25th, 2016

Borrowing from pastry chefs, engineers create nanolayered composites: Method to stack hundreds of nanoscale layers could open new vistas in materials science July 25th, 2016

Integration of novel materials with silicon chips makes new 'smart' devices possible July 25th, 2016

Molecular Nanotechnology

New remote-controlled microrobots for medical operations July 23rd, 2016

Scientists develop way to upsize nanostructures into light, flexible 3-D printed materials: Virginia Tech, Livermore National Lab researchers develop hierarchical 3-D printed metallic materials July 20th, 2016

Pushing a single-molecule switch: An international team of researchers from Donostia International Physics Center, Fritz-Haber Institute of the Max Planck Society, University of Liverpool, and the Polish Academy of Sciences has shown a new way to operate a single-molecule switch July 19th, 2016

Researchers harness DNA as the engine of super-efficient nanomachine: New platform detects traces of everything from bacteria to viruses, cocaine and metals July 10th, 2016

Optical computing/Photonic computing

Attosecond physics: Mapping electromagnetic waveforms July 25th, 2016

The birth of quantum holography: Making holograms of single light particles! July 21st, 2016

Researchers develop faster, precise silica coating process for quantum dot nanorods July 12th, 2016

A little impurity makes nanolasers shine: ANU media release July 6th, 2016

Discoveries

Attosecond physics: Mapping electromagnetic waveforms July 25th, 2016

Borrowing from pastry chefs, engineers create nanolayered composites: Method to stack hundreds of nanoscale layers could open new vistas in materials science July 25th, 2016

Integration of novel materials with silicon chips makes new 'smart' devices possible July 25th, 2016

Accurate design of large icosahedral protein nanocages pushes bioengineering boundaries: Scientists used computational methods to build ten large, two-component, co-assembling icosahedral protein complexes the size of small virus coats July 25th, 2016

Announcements

Borrowing from pastry chefs, engineers create nanolayered composites: Method to stack hundreds of nanoscale layers could open new vistas in materials science July 25th, 2016

Integration of novel materials with silicon chips makes new 'smart' devices possible July 25th, 2016

Accurate design of large icosahedral protein nanocages pushes bioengineering boundaries: Scientists used computational methods to build ten large, two-component, co-assembling icosahedral protein complexes the size of small virus coats July 25th, 2016

XEI Scientific Partners with Electron Microscopy Sciences to Promote and Sell its Products in North and South America July 25th, 2016

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

Attosecond physics: Mapping electromagnetic waveforms July 25th, 2016

Borrowing from pastry chefs, engineers create nanolayered composites: Method to stack hundreds of nanoscale layers could open new vistas in materials science July 25th, 2016

Integration of novel materials with silicon chips makes new 'smart' devices possible July 25th, 2016

Accurate design of large icosahedral protein nanocages pushes bioengineering boundaries: Scientists used computational methods to build ten large, two-component, co-assembling icosahedral protein complexes the size of small virus coats July 25th, 2016

Photonics/Optics/Lasers

Attosecond physics: Mapping electromagnetic waveforms July 25th, 2016

RMIT researchers make leap in measuring quantum states July 21st, 2016

The birth of quantum holography: Making holograms of single light particles! July 21st, 2016

Graphene photodetectors: Thinking outside the 2-D box July 21st, 2016

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







Car Brands
Buy website traffic