A British research
team has made it into the record books by creating the
smallest "test tubes" known to science.
Materials scientists from Oxford and Nottingham universities
performed chemical reactions inside tiny tubes of carbon
atoms known as nanotubes.Essentially,
these are sheets of graphite an atom thick that are folded
back on themselves to form cylinders.
They were used to force
molecules into long straight chains, reports the journal
Chemical Communications.David
Britz, at Oxford, and Andrei Khlobystov, at Nottingham,
were able to observe the results of these reactions with
an electron microscope.
The work has made it into the Guinness
Book of World Records. The nano-sized test tubes are so
tiny that around 300 billion would fit on to a full stop.
The technique could help improve
industrial processes employing reactions in which single
molecules join together to form long chains called polymers.
Chain reaction
In this study, the molecules being
joined were buckminsterfullerene oxides. Under normal
circumstances, these would connect up into a twisted polymer
that has many branches, like a tree.When
the same reactions take place in the nanotubes, the oxides
are forced into a straight line with no branches. This
is because they are confined by the nanotube.
In other words, the molecules formed
a much better quality polymer when the reaction took place
inside the tubes. "The
idea is that you can make the same materials you made
before but potentially much more easily, at a cheaper
price and with fewer environmental controls," Mr
Britz told the BBC News website.
So far, the researchers have only
reacted buckminsterfullerene oxide inside the nanotubes.
But they envisage that important
polymers such as polyethylene, whose molecular shape is
straightforward to control, could potentially be synthesised
inside nanotubes.
'Sky's the limit'
Catalysts currently used to make
straight-chain (high quality) polyethylene are sensitive
to air and water. This means the material has to be synthesised
in vats with a carefully controlled environment. Nano-test
tubes could possibly provide an alternative to this process.
But, said Andrei Khlobystov at Nottingham:
"More studies are needed to understand how our method
can be used for real, practical applications" And
Mr Britz added: "[Our technique] is generally a way
to constrain what you're making - to remove a degree of
freedom when you're carrying out a reaction." The
tiny test tubes have an inner diameter of about 1.2 nanometres
(billionths of a metre) and they are about two micrometres
(millionths of a metre) long.
They have a volume of two "zeptolitres".
The zeptolitre is currently the second smallest defined
unit of volume.Researchers
hope that the technique could also be used to synthesise
entirely new types of materials.
"As far as new materials
are concerned, the sky is the limit. With enough creativity
you could come up with plenty of uses for one-dimensional
cavities," said Mr Britz.
