Nanotechnology Now

Our NanoNews Digest Sponsors


Heifer International

Wikipedia Affiliate Button


DHgate

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

A compact, efficient single photon source that operates at ambient temperatures on a chip: Highly directional single photon source concept is expected to lead to a significant progress in producing compact, cheap, and efficient sources of quantum information bits for future appls May 3rd, 2016

Nuclear pores captured on film: Using an ultra fast-scanning atomic force microscope, researchers from the University of Basel have filmed 'living' nuclear pore complexes at work for the first time May 3rd, 2016

Little ANTs: Researchers build the world's tiniest engine May 3rd, 2016

An Experiment Seeks to Make Quantum Physics Visible to the Naked Eye May 3rd, 2016

Display technology/LEDs/SS Lighting/OLEDs

Hybrid nanoantennas -- next-generation platform for ultradense data recording April 28th, 2016

Manipulating light inside opaque layers April 24th, 2016

Highlights from the Graphene Flagship April 22nd, 2016

What screens are made of: New twists (and bends) in LCD research: X-ray research at Berkeley Lab details exotic structure formed by liquid crystals April 19th, 2016

Govt.-Legislation/Regulation/Funding/Policy

A compact, efficient single photon source that operates at ambient temperatures on a chip: Highly directional single photon source concept is expected to lead to a significant progress in producing compact, cheap, and efficient sources of quantum information bits for future appls May 3rd, 2016

Little ANTs: Researchers build the world's tiniest engine May 3rd, 2016

An Experiment Seeks to Make Quantum Physics Visible to the Naked Eye May 3rd, 2016

Making invisible physics visible: The Jayich Lab has created a new sensor technology that captures nanoscale images with high spatial resolution and sensitivity May 2nd, 2016

Molecular Nanotechnology

Little ANTs: Researchers build the world's tiniest engine May 3rd, 2016

Researchers create artificial protein to control assembly of buckyballs April 27th, 2016

Physicists build engine consisting of one atom: World's smallest heat engine uses just a single particle April 17th, 2016

Physicists prove energy input predicts molecular behavior: Theoretical proof could lead to more reliable nanomachines March 22nd, 2016

Optical computing/ Photonic computing

A compact, efficient single photon source that operates at ambient temperatures on a chip: Highly directional single photon source concept is expected to lead to a significant progress in producing compact, cheap, and efficient sources of quantum information bits for future appls May 3rd, 2016

Researchers create a first frequency comb of time-bin entangled qubits: Discovery is a significant step toward multi-channel quantum communication and higher capacity quantum computers April 28th, 2016

Hybrid nanoantennas -- next-generation platform for ultradense data recording April 28th, 2016

NREL theory establishes a path to high-performance 2-D semiconductor devices April 27th, 2016

Discoveries

A compact, efficient single photon source that operates at ambient temperatures on a chip: Highly directional single photon source concept is expected to lead to a significant progress in producing compact, cheap, and efficient sources of quantum information bits for future appls May 3rd, 2016

Nuclear pores captured on film: Using an ultra fast-scanning atomic force microscope, researchers from the University of Basel have filmed 'living' nuclear pore complexes at work for the first time May 3rd, 2016

Little ANTs: Researchers build the world's tiniest engine May 3rd, 2016

An Experiment Seeks to Make Quantum Physics Visible to the Naked Eye May 3rd, 2016

Announcements

A compact, efficient single photon source that operates at ambient temperatures on a chip: Highly directional single photon source concept is expected to lead to a significant progress in producing compact, cheap, and efficient sources of quantum information bits for future appls May 3rd, 2016

Nuclear pores captured on film: Using an ultra fast-scanning atomic force microscope, researchers from the University of Basel have filmed 'living' nuclear pore complexes at work for the first time May 3rd, 2016

Little ANTs: Researchers build the world's tiniest engine May 3rd, 2016

An Experiment Seeks to Make Quantum Physics Visible to the Naked Eye May 3rd, 2016

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

A compact, efficient single photon source that operates at ambient temperatures on a chip: Highly directional single photon source concept is expected to lead to a significant progress in producing compact, cheap, and efficient sources of quantum information bits for future appls May 3rd, 2016

Nuclear pores captured on film: Using an ultra fast-scanning atomic force microscope, researchers from the University of Basel have filmed 'living' nuclear pore complexes at work for the first time May 3rd, 2016

Little ANTs: Researchers build the world's tiniest engine May 3rd, 2016

An Experiment Seeks to Make Quantum Physics Visible to the Naked Eye May 3rd, 2016

Photonics/Optics/Lasers

A compact, efficient single photon source that operates at ambient temperatures on a chip: Highly directional single photon source concept is expected to lead to a significant progress in producing compact, cheap, and efficient sources of quantum information bits for future appls May 3rd, 2016

Exploring phosphorene, a promising new material April 29th, 2016

Researchers create a first frequency comb of time-bin entangled qubits: Discovery is a significant step toward multi-channel quantum communication and higher capacity quantum computers April 28th, 2016

Hybrid nanoantennas -- next-generation platform for ultradense data recording April 28th, 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