The surface features formed by a eucalyptus species in southwest Australia waxes gives the plant remarkable wetting and self-cleaning properties that could be replicated for use in nanotechnology products. |
Murdoch
University nano scientists have discovered that a eucalyptus plant
native to south west WA has unique self-cleaning and water-repellent
properties which could make it a gold mine for new nanotechnology
applications.
The
Mottlecah, which is also known as The Rose of the West for its large
spectacular flowers, has silvery leaves which are covered in a wax which
produces nano-sized bumps and pillars. This causes water to form
droplets that roll over the surface of the leaves and fall towards the
root system of the plant, picking up any dirt along the way.
These properties, which are known as superhydrophobic and
self-cleaning, are similar to the lotus plant’s which has inspired a
range of self-cleaning and anti-bacterial technologies currently being
developed.
Dr.
Gerrard Eddy Jai Poinern and his team at the Murdoch Applied
Nanotechnology Research Group say their discovery has the potential to
be applied in a variety of ways, from so-called lab-on-a-chip settings
in medical research, to the treatment of ships’ hulls to help prevent
the build up of harmful microorganisms, plants and animals.
“I
had noticed these incredible plants on the Murdoch campus because of
the unusual appearance of their leaves,” said Poinern, who is based at
the School of Engineering and Energy. “They made me wonder whether the
plant had superhydrophobic properties and so began our research
investigation.
“One
of the experiments we carried out was to coat the leaf with carbon
black toner from a laser printer cartridge and then observe how the
rolling drops of water were able to completely clean the surface of the
leaf.
“This
was because the surface features formed by this Eucalyptus’ waxes gave
the leaves remarkable wetting and self-cleaning properties. We believe
this enhances the plant’s survival in an arid climate because it is able
to source and effectively manage its water usage through channelling
any water to its roots.
“In this way the Mottlecah is unusual because most superhydrophobic plants are usually found in aquatic settings.”
Poinern
and his team also extracted waxes from the leaves and found that they
were capable of self-reassembly. When coated on laboratory glass slides,
the wax formed features which mimicked the complex 3-D geometry of the
nano-sized bumps and pillars found on the original leaf surface, making
the slide superhydrophobic.
“It
was fairly easy and inexpensive to extract the wax from the leaves and
yet the wax still had these remarkable qualities,” said Poinern. “When
the tested glass slides were placed horizontally onto a water surface,
the added buoyancy support of the wax meant that it was able to carry a
greater load than the uncoated slides.
“In
microfluidic devices used in advanced medical research and disease
testing, such coatings could help to maintain the sterility of devices
which need to be used over and over again.
“In
fact there are a number of potential applications and we are sure there
are other WA native plants which have similar properties. We hope to
continue our research to find out more about these properties and how
they can be fully utilized.”
