Soft polymerization of hexamethyldisiloxane by coupling pulsed direct‐liquid injections with dielectric barrier discharge

This work examines the combination of pulsed direct‐liquid injections with dielectric barrier discharge at atmospheric pressure for the deposition of organosilicon coatings using hexamethyldisiloxane (HMDSO) as the precursor and nitrogen as the carrier gas. In such conditions, deposition relies on the charging of micrometer droplets and their transport toward the substrate by the Coulomb force. The thin‐film morphology and extent of precursor fragmentation are strongly linked to the amount of energy provided by the filamentary discharge to HMDSO droplets. While cross‐linked and smooth coatings were achieved at low energies as in standard gas phase plasma polymers, viscous and droplet‐like structured thin films were deposited at higher energies. The latter material is attributed to the soft polymerization of HMDSO droplets related to plasma–droplet interactions. Pulsed aerosol‐assisted plasma processes are investigated. Here, it is focused on the combination of hexamethyldisiloxane (HMDSO) injections with dielectric barrier discharge at atmospheric pressure produced in nitrogen. In contrast with the classical plasma‐enhanced‐chemical vapor deposition processes that are forming cross‐linked materials, droplet injection enables to form viscous and micro‐structured thin films depending of the energy in the discharge. Such feature is attributed to the soft polymerization of HMDSO droplets related to plasma–droplet interactions.