Carbon 'fluffy' aggregates produced by helium - hydrocarbon high
  pressure plasmas as analogs to interstellar dust
  The present study provides an investigation on the deposition of
carbon-related products on different substrates using a high power dielectric
barrier discharge fed with helium and saturated hydrocarbon gases. The
discharge has been characterized by means of voltage-current measurements,
while the neutral species and the dissociation compounds accumulated in the
plasma reactor have been analyzed by Fourier-transform infrared (FTIR)
spectroscopy. The properties of non-aromatic hydrogenated amorphous carbon
(a-C:H) films and 'fluffy' carbon dust deposited onto various substrates are
analyzed by FTIR and X-ray photoelectron spectroscopy. The sp2-hybridized
fraction of a-C:H films is negligible while for the 'fluffy' dust, does not
exceed 10%. The microscopic appearance, the hierarchical organization and the
CH2 / CH3 ratio around 2 of the 'fluffy' dust analog are results that supports
the current understanding of cosmic carbon dust physico-chemical properties.
