This is a really neat piece of work that uses some
of the qualities of a Mobius strip although I am not sure that this is real Mobius
strip from this item. It sounds good
though and the picture is convincing.
The point is that we are playing with this stuff in
this way and great surprises can be expected.
Nothing obvious is indicated as yet.
All good
Mobius strip ties liquid
crystal in knots to produce tomorrow's materials and photonic devices
by Staff Writers
Warwick, UK (SPX) Aug 26, 2013
A Mobius 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.
University of Warwick
scientists have shown how to tie knots in liquid crystals using a miniature
Mobius 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 Mobius strip.
A Mobius 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."
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.
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