Home' Defence Magazine : Defence Magazine Issue 1 2018 Contents R
ESEARCHER Richard Piola is shining
a light on fouling. He has been working
with Dutch company Royal Philips on a
novel approach to combating biofouling
using ultraviolet light.
“The fundamental idea is to have a type of coating
which emits UV light outward from the surface as
opposed to traditional methods of UV antifouling that
direct an external light onto a surface,” Richard says.
His team at DST has been testing the technology
at a site in Melbourne and is now testing it in tropical
waters near Cairns.
“Test results are consistent; surfaces are kept
completely free from fouling for prolonged periods,
regardless of location or circumstances. And this is
achieved at very low power levels at the surface, in
the order of 1mW of UV light per square metre,” he
This system works because the DNA of the colo-
nising organisms absorbs UV light. When this occurs
chemical bonds are broken, genetic codes are dam-
aged and the organisms cannot replicate.
The Philips’s collaboration came about, as many
good ideas do, via a conference.
While UV light has been used to control water-
borne organisms for decades, Richard became aware
of Philips’ novel use of LEDs embedded in silicone
films to turn underwater surfaces into UV light emit-
“We saw that this could be applied to com-
plex-shaped vessel niche areas and other surfaces
such as sensors,” Richard says.
“These are areas that have always been problem-
atic as they’re not conducive to the effective use of
traditional antifouling coatings that perform well on
“Philips were interested in testing the concept
under a wider range of environmental conditions, and
they were enthusiastic about us joining the research
because of Australia’s expansive coastline and wide
range of biofouling pressures.”
Following a pilot study on a first generation panel
and after providing feedback into the redesign of a
second generation panel, testing over the last year
and a half has shown the system works well.
Richard has tested the UV panel, which has 10
LEDs in a slab of silicone of about 30 x 30cm, in a
number of scenarios such as static and flowing water
and is now trialling a panel at DST’s tropical expo-
“At the Melbourne marine site, we bring the test
item up every month for evaluation,” he says.
“It is showing some signs of wear and tear and a
degradation in the LEDs has seen a reduction in the
effective antifouling area over time.
“This is expected as the optical properties of the
silicone have changed over time, but we have exceed-
ed Philips’s expectation of what would be possible,
and shown that this technology is really promising.”
The flexible silicone covering can be moulded to
fit different shapes, making it a novel solution that
will be useful in a number of situations. It’s also
non-toxic, unlike some traditional techniques.
“Our results indicate that, given energy losses,
a realistic consumption of 1mW per square metre
is required for effective biofouling and that’s really
quite low,” Richard says.
“We haven’t done a study of the duty cycles
required, in other words how often the light needs to
be turned on, but indications are that it doesn’t need
to be continuous, even an hour a day is enough to kill
anything settling during the intervening periods.
“That needs further assessment, and the sweet
spot will depend on the environment.”
Philips has partnered with AkzoNobel to com-
mercialise the technology. Going forward, the focus
will be on optimising the technology for low power,
covering larger areas, and making the films thinner
and more flexible.
DST is looking at extending this basic UV radia-
tion concept into the area of optical sensor anti-foul-
ing. There are currently various methods such as
wipers used to protect optics but they aren’t very
Richard’s team is working with the Australian
Institute of Marine Science in Townsville to examine
the potential of using internally refracted UV light to
keep the lens of optical sensors free of fouling.
DST researchers Dr Richard Piola and Clare Grandison inspect a test panel fitted with a novel UV panel system that aims to deter fouling.
Defence Issue 1 2018
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