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ADVANCED MATERIALS & PROCESSES •
NOVEMBER-DECEMBER 2014
15
Low Temperature Plasma Process
Effectively Modifies Surface of Graphene
G
raphene has long been hailed as a
super-material with the potential to
revolutionize industry. Concepts sur-
rounding electronic and mechanical applica-
tions have been around since the 1950s, but it
was not until 2004 that researchers isolated the
2D material by separating graphite using adhe-
sive tape. Andre Geim and Konstantin
Novoselov’s groundbreaking research elevated
this material onto the world stage.
Graphene’s potential for industrial and
commercial applications is staggering—
experimental characterization reveals that
this promising material is mechanically 200
times stronger than steel, has in-plane elec-
trical and thermal conductivity higher than
copper, and features a surface area greater
than 2500 m
2
/g (Fig. 1).
The term
graphene,
which originally de-
scribed a single 2D sheet of carbon atoms, has
gradually expanded to encompass both sheet
and flake carbon materials that can be pro-
duced by different methods. Engineering appli-
cations tend to focus on graphene nanoplatelets
(GNPs), which can be produced by a
top-down
production method that involves exfoliating
mined graphite to produce flakes, or a
bottom-
up
method such as chemical vapor deposition
from a carbon source. Both techniques have ad-
vantages and disadvantages and, for potential
end users, represent alternative sources to en-
sure a consistent, secure supply.
Global interest in graphene has been stim-
ulated by its extraordinary properties, which
are not only of interest to the academic world,
but also investors and industry stakeholders
seeking to incorporate the wonder material
into commercial products. Its properties ap-
pear to have nearly limitless uses, including
composite materials for aerospace, energy har-
vesting and storage in batteries and superca-
pacitors, flexible displays and optical
electronics, and numerous applications in
healthcare and medical devices.
IDTechEx Ltd., UK, estimates that the
graphene industry will grow from its current
market value of $20 million to more than $390
million by 2024
[1]
, with the greatest expansions
forecast in energy storage, transparent conduc-
tive films, and composite materials. These mar-
kets alone represent significant benefits, but
even with clearly defined market needs, trans-
lating scientific developments into commercial
reality is a complex process rife with technolog-
ical hurdles.
Graphene for commercial use
The substantial number of graphene related
patents reported by the UK’s Intellectual Prop-
erty Office (IPO) indicates not only graphene’s
potential, but that both academic and industry
believe it can be made to work. By February
2013, 8416 patents had been published world-
wide, and rose to 11,372 at the beginning of
2014
[2]
. Patents are applied for continually, with
approximately 80% held by organizations in
China, the U.S., Korea, and Japan. Most relate
to potential applications and products, as op-
posed to raw material production.
Despite the rapid growth of patent applica-
tions, many academic, commercial, and finan-
cial critics express doubts as to whether the
material can become a commercial success
through incorporation into next-generation
products and applications. It is well known that
excellent laboratory results do not always trans-
late into large-scale applications, particularly if
there is a cost premium.
While a significant proportion of graphene
research currently focuses on producing uni-
form single-layer graphene sheets (predomi-
nantly by Asian electronics giants LG and
Samsung for use in electrical applications), an
alternative approach is more relevant to solv-
ing engineering challenges. The approach fo-
cuses on the particulate graphene form, which
Martin Kemp
Haydale Ltd.
South Wales, UK
Harnessing
graphene’s
potential for
commercial
use requires
attaining
homogeneous
dispersion
and strong
chemical
bonding with
the matrix of
a target
material.
This can be
achieved by
effective
surface
modification.
Fig. 1 —
Graphene has incredible intrinsic properties, showing great potential for
industrial and commercial applications across a wide range of industries.