Synthesis and Characterization of Polypyrrole-Coated Anthracene Microparticles: A New Synthetic Mimic for Polyaromatic Hydrocarbon-based Cosmic Dust

LASP Science Seminars

Synthesis and Characterization of Polypyrrole-Coated Anthracene Microparticles: A New Synthetic Mimic for Polyaromatic Hydrocarbon-based Cosmic Dust

Prof. Steven P. Armes (Department of Chemistry, University of Sheffield)
July 7, 2022
16:00 MT/MDT
SPSC-W120 and Zoom

Polyaromatic hydrocarbons (PAHs) are found throughout the Universe. The ubiquity of these organic molecules means that they are of considerable interest in the context of cosmic dust, which typically travel at hypervelocities (> 1 km s-1) within our Solar System. However, studying such fast-moving micrometer-sized particles in laboratory-based experiments requires suitable synthetic mimics. Herein we use ball-milling to produce microparticles of anthracene, which is the simplest member of the PAH family. Size control can be achieved by varying the milling time in the presence of a suitable anionic commercial polymeric dispersant (Morwet D-425). These anthracene microparticles are then coated with a thin overlayer of polypyrrole (PPy), which is an air-stable organic conducting polymer. The uncoated and PPy-coated anthracene microparticles are characterized in terms of their particle size, surface morphology and chemical structure using optical microscopy, scanning electron microscopy, laser diffraction, aqueous electrophoresis, FT-IR spectroscopy, Raman microscopy and XPS. Finally, such microparticles can be accelerated up to hypervelocities using a Light Gas Gun. Moreover, studies of impact craters indicate carbon debris so they are expected to serve as the first synthetic mimic for PAH-based cosmic dust.

Upcoming Science Seminars:
Aug. 18, 2022
The Dispersal of Gas in Circumstellar Disks Based on Observations of H_2 in the FUV
Laura Flagg (Cornell University)