Carbon 'fluffy' aggregates produced by helium - hydrocarbon high pressure plasmas as analogs to interstellar dust

TL;DR

This study investigates the formation of carbon 'fluffy' aggregates in high-pressure helium-hydrocarbon plasmas, providing insights into their potential as analogs for interstellar dust through detailed spectroscopic and microscopic analysis.

Contribution

It introduces a novel plasma-based method to produce carbon dust analogs with properties similar to interstellar dust, advancing astrochemical research.

Findings

'Fluffy' carbon dust exhibits hierarchical organization and specific CH2/CH3 ratios.

The 'fluffy' dust has a low sp2-hybridized carbon fraction, akin to cosmic dust.

The plasma process effectively deposits carbon materials with interstellar dust-like properties.

Abstract

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.