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Page 58
November 13-14, 2017 Paris, France
5th International Conference on
PLASMA CHEMISTRY AND
PLASMA PROCESSING
Journal of Biotechnology and Phytochemistry
Volume 1, Issue 2 Plasma Chemistry 2017
Superior functional plasma coating from
protonated precursor ions via the plasma α-γ
transition
Solmaz Saboohi1 , Bryan R Coad1 , Hans J Griesser1, Andrew
Michelmore1,2 and Robert D Short1, 3
1Future Industries Institute - University of South Australia, Australia
2University of South Australia, Australia
3University of Lancaster, UK
C hemically functionalized surfaces may be produced
via plasma polymerization; however, a high degree of
functional group retention is often difficult to achieve. Here,
the plasma polymerization of three structurally related ester
precursors, ethyl isobutyrate (EIB), methyl isobutyrate (MIB)
and ethyl trimethylacetate (ETMA) is compared at low and
high pressure. In moving from a low pressure to higher
pressure regime, significant changes in the plasma chemistry
and resulting plasma polymer deposit were observed with
much higher retention of chemical functionality at the higher
pressure observed. Until now these changes would have been
attributed to a decrease in the energy/molecule, however we
show by direct measurement of the chemistry and physics of
the plasma that there is fundamental shift in the properties
of the plasma and surface interactions which explain the
results. At low pressure (α regime) precursor fragmentation
and neutral deposition dominate resulting in poor functional
group retention. Increasing the pressure such that the sheath
region close to surfaces becomes collisional (γ regime)
favours production of protonated precursor ions which retain
functionality and dominate the deposition process rather
than radical species.
J Biot Phyt 2017