This paper focuses on the understanding of the main mechanisms that participate in the growth process of an SiO2‐like film in an atmospheric pressure Townsend discharge in N2 with small ad‐mixtures of HMDSO and N2O. The approach consists of analyzing the influence of operating parameters on the growth rate profile through a fluid dynamics model. The suggested chemical mechanism is constituted by one volume reaction and one surface reaction. This simple model enables us to assume which phenomena control the film growth process among the following mechanisms: HMDSO dissociation by N2(A3Σ) in Si‐containing radicals, radicals transport to the surface, and surface activation process by plasma.magnified image

A coating with anti-fog properties was developed for a polycarbonate (PC) substrate using a multi-step process. A silicon-containing multilayer was first deposited by atmospheric pressure Townsend discharge (APTD) using hexamethyldisiloxane (HMDSO) precursor to ensure cohesion between the coating and the PC and to protect the polymer against dissolution in solvents during subsequent spin-coating processes. The multilayer was also developed in a nitrogen environment in order to provide amino groups on the surface, which allowed for the subsequent covalent bonding of the anti-fog layer. This antifog layer was made of a spin-coated (poly(ethylene-maleic anhydride) (PEMA) layer, used as a linking arm, followed by a spin-coated poly(vinyl alcohol) (PVA) layer, for its anti-fog properties. Surface analyses (XPS, FTIR, and AFM) confirmed that the silicon-containing multilayer was successfully deposited with a good control obtained for each step. The antifog coating, also tested with promising results, displayed a negligible loss of optical transmission across the visible spectrum.