Silicon oxide deposition from cold remote plasma on polyethylene powders in fluidized bed

Abstract

In this work, a fluidized bed has been coupled to a far cold remote nitrogen/oxygen plasma to deposit silicon oxide SiOx from silane SiH4 on the surface of a polyethylene powder. The influence on the characteristics of the silica-like deposit on powders, of several parameters such as the amount of oxygen injected in the plasma, the SiH4 flow rate and the treatment duration, has been studied. First, the particles wettability has been measured by contact angle (Washburn method), knowing that PE is hydrophobic and that silicon oxide would increase its hydrophilicity. The film chemical composition has been analysed by FT-IR spectroscopy. Its organization on the powder surface and its morphology have been studied by FEG SEM. Results indicate that the wettability of powders increases with the whole parameters studied. Deposition seems to occur under the form of nodules; its continuity is not ascertained. This is the reason why the increase of wettability could be due either to a better surface coverage of the deposition or to an increase of its thickness. Additional analyses are in progress to better understand the correlations between the deposition parameters, the plasma features and the deposition characteristics.