Mobius strip ties liquid crystal in knots to produce tomorrow’s materials and photonic devices

This shows liquid crystal knots created around miniature Möbius strip particles (simulation). Different knots are produced by strips with different numbers of twists. The central part of the knot is shown in red around the strip in blue. Examples are…

This shows liquid crystal knots created around miniature Möbius strip particles (simulation). Different knots are produced by strips with different numbers of twists. The central part of the knot is shown in red around the strip in blue. Examples are shown for (A) two (Hopf link), (B) three (trefoil knot), (C) four (Solomon’s knot) and (D) five (cinquefoil knot) twists. Credit: University of Warwick

University of Warwick scientists have shown how to tie knots in liquid crystals using a miniature Möbius strip made from silica particles.

By tying substances like this in knots, the researchers hope to understand how their intricate configurations and unique properties can be harnessed in the next generation of advanced materials and photonic devices.
Liquid crystal is an essential material in modern life – the flat panel displays on our computers, TVs and smartphones all make use of its light-modulating properties.

It is composed of long, thin, rod-like molecules which align themselves so they all point in the same direction. By controlling the alignment of these molecules, scientists can literally tie them in a knot.
To do this, they simulated adding a micron sized silica particle – or colloid – to the liquid crystal. This disrupts the orientation of the liquid crystal molecules.

For example, a colloid in the shape of a sphere will cause the liquid crystal molecules to align perpendicular to the surface of the sphere, a bit like a hedgehog’s spikes.
Using a theoretical model, the University of Warwick scientists have taken this principle and extended it to colloids which have a knotted shape in the form a Möbius strip.

Enlarge

This is a visualization of the average configuration of the molecules in a liquid crystal knot (simulation). (A) A plane cross-section of the knot with the molecular alignment indicated by small cylinders. The grey rectangles correspond to a part of the particle and the red spots highlight central portions of the knot. (B) A full three-dimensional visualization with molecular orientation shown as a color map. Different colors correspond to different orientations as given in the inset. Credit: University of Warwick
A Möbius strip with one twist does not form a knot, however with three, four and five twists it becomes a trefoil knot (like an overhand knot with the ends joined together), a Solomon’s knot or a cinquefoil knot respectively.
By adding these specially designed knotted particles they force the liquid crystal to take on the same structure, creating a knot in the liquid crystal.
Gareth Alexander, Assistant Professor in Physics and Complexity Science, at the University of Warwick said: “Knots are fascinating and versatile objects, familiar from tying your shoelaces.
“Recently it has been demonstrated that knots can be created in a variety of natural settings including electromagnetic fields, laser light, fluid vortices and liquid crystals.
“These knots are more intricate than those in your shoelaces, since it is the entire continuous material, and not just a piece of string, that is knotted.
“Our research extends this previous work to apply to liquid crystal, the substance we use every day in our TVs, smartphones and computer screens.
“We are interested in this as creating and controlling these intricate knotted fields is an emergent avenue for the design of new metamaterials and photonic devices.”

Explore further:

Physics duo create first knotted vortex in a fluid (w/ video)

More information: The study, published in the journal PNAS, is entitled “Knots and nonorientable surfaces in chiral nematics” and is authored by Thomas Machon and Gareth Alexander, both jointly based in the Department of Physics and the Centre for Complexity Science at the University of Warwick. www.pnas.org/content/early/2013/08/09/1308225110.abstract

Journal reference:

Proceedings of the National Academy of Sciences

Provided by

University of Warwick

view popular

5 /5 (9 votes)

Related Stories

Silica microspheres in liquid crystals offer the possibility of creating every knot conceivable

Aug 19, 2011

Knots can now be tied systematically in the microscopic world. A team of scientists led by Uros Tkalec from the Jozef Stefan Institute in Ljubljana (Slovenia), who has been working at the Max Planck Institute …

Physics duo create first knotted vortex in a fluid (w/ video)

Mar 04, 2013

(Phys.org) —Physicists William Irvine and Dustin Kleckner of the University of Chicago, have for the first time, created a knotted vortex in a fluid. They describe how they printed 3D airfoils and then …

Chemistry researchers create self-tying knotted molecules in the lab

Nov 09, 2012

(Phys.org)—A group of chemistry researchers working in a lab at Cambridge University have succeeded in causing a group of molecules to form themselves into trefoil knots. The team was working on combinatorial …

Tying molecules in knots

Nov 07, 2011

A new generation of lighter, stronger plastics could be produced using an intricate chemical process devised by scientists.

Simulation shows colloids can form into non-crystalline state at below freezing temperatures

Aug 07, 2013

(Phys.org) —Two researchers working at Universita di Roma, Frank Smallenburg and Francesco Sciortino have shown via computer simulation that certain colloids can be made to form into a stable non-crystalline …

A revolution in knot theory

Nov 10, 2011

In the 19th century, Lord Kelvin made the inspired guess that elements are knots in the “ether”. Hydrogen would be one kind of knot, oxygen a different kind of knot—-and so forth throughout the periodic table …

Recommended for you

Planes, trains and molecules: Deriving a generic routing algorithm from the physics of interacting polymers

17 hours ago

Finding a single optimal route is easy, but optimizing the combination of multiple routes is a challenge found in a wide range of applications including Internet instant messaging, peer-to-peer networks, subway …

New findings on how the ear hears could lead to better hearing aids

20 hours ago

A healthy ear is much better at detecting and transmitting sound than even the most advanced hearing aid. But now researchers reporting in the August 20 issue of the Biophysical Journal, a Cell Press public …

Researchers develop model to help control cascading events

Aug 19, 2013

(Phys.org) —A team of researchers at the University of California has developed a model that might lead to a better way to control natural cascading events such as landslides, earthquakes, or even neural …

Bright light, big mirror: Precision X-ray focusing at NSLS-II

Aug 16, 2013

(Phys.org) —Why does a packet of electrons whizzing around a half-mile ring at nearly the speed of light need a state-of-the-art mirror? It’s not to check its hair, that’s for sure.

Try clapping your wet hands: A physics lesson from Virginia Tech engineers

Aug 15, 2013

Sunny Jung continues to redefine the views on the laws of physics, and in doing so, impacts the research on topics as varied as drug delivery methods to fuel efficiency.

One-of-a-kind spectrometer reads vibrations between atoms to find structures of molecules

Aug 15, 2013

A Rice University laboratory has improved upon its ability to determine molecular structures in three dimensions in ways that challenge long-used standards.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

More news stories

Teleportation just got easier—but not for you, unfortunately

Thanks to two studies published in Nature last Thursday, the chance of successful teleportation has considerably increased. Which is a good thing, right? …

Planes, trains and molecules: Deriving a generic routing algorithm from the physics of interacting polymers

Finding a single optimal route is easy, but optimizing the combination of multiple routes is a challenge found in a wide range of applications including Internet instant messaging, peer-to-peer networks, subway …

Researchers discover quantum algorithm that could improve stealth fighter design

(Phys.org) —Researchers at the Johns Hopkins University Applied Physics Laboratory (APL) have devised a quantum algorithm for solving big linear systems of equations. Furthermore, they say the algorithm could be used to …

New findings on how the ear hears could lead to better hearing aids

A healthy ear is much better at detecting and transmitting sound than even the most advanced hearing aid. But now researchers reporting in the August 20 issue of the Biophysical Journal, a Cell Press public …

‘Listening’ to black holes form with gravity waves

New technology that breaks the quantum measurement barrier has been developed to detect the gravity waves first predicted by Einstein in 1916.

World’s first 2560×1440 Quad HD LCD panel for smartphones

LG Display, a leading innovator of display technologies, announced today that it has developed the world’s first Quad HD AH-IPS LCD panel for smartphones. At 2560×1440 with 538ppi, the new 5.5-inch Quad HD …

Daily life shapes sustainable transportation

Imagine your life recreated in data, every car trip, bus ride, grocery store stop and burrito run—including when, why, and with whom you went—represented by blips on a computer.

New strategy tests for lethal stage of TB in Asia

More than 20,000 people in Pakistan are being tested for the potentially deadly stage of tuberculosis using a new strategy developed at UC Davis Health System to effectively detect the disease in children for the first time.

Fertility and weight relationship investigated

A peptide that controls appetite and metabolism is at the centre of research which aims to give insight into how peptides affect fertility.

Federal agencies remapping coastal areas damaged by Hurricane Sandy

A day after the administration released the Hurricane Sandy Rebuilding Task Force progress report, three federal agencies have announced plans for remapping parts of the East Coast, where Hurricane Sandy …