A coating that needs only water to
remove oil has been developed by a
team at Purdue University, Indiana,
US. ‘You add water, and the oil just
comes right off like magic,’ said
lead researcher Jeffrey Youngblood.
‘These are eco-friendly coatings
– environmentally “green” in the
sense that they eliminate the need
for harsh detergents and solvents in
settings ranging from home kitchens
to industrial machine shops that must
contend with heavy oil spills.’
The coatings have a bottom layer
of polyethylene glycol, which attracts
water, and a top layer that prevents
the passage of oil, and can be applied
to glass, plastics, fabrics and a wide
range of other materials. Any oil on
the surface of the coating can be
removed by wiping with water. The
coatings can also be used as antifogging
coatings for windscreens
and spectacles.
The solvent soluble coatings were
produced by the copolymerisation of
perfluorinated end-cap polyethylene
glycol (f-PEG) amphiphilic macromers
with a variety of comonomers. The
f-PEG component has previously
been shown to be stimuli-responsive,
showing both oleophobic and
hydrophilic behaviour, according to
Youngblood. The proportion of the
comonomer was varied to determine
the minimum level of surface activity
needed to produce the self-cleaning
characteristics.
Meanwhile, another group of
researchers has been examining
the use of depth profile X-ray
photoelectron spectroscopy to
examine the performance of
antireflective and antismudge
coatings, applied to the screens
of consumer electronics products
such as mobile phones and mp3
players. Steven Carlo, from C3
Consulting, Maryland, US, said that
the structure and mechanisms of
these coatings, generally based on
perfluoroalkyl ethers with layers of
silica and aluminium, are poorly
understood and this new approach
could determine the composition
and chemistry to facilitate the
development of improved coatings.
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