Low temperature silicon oxide deposition on polymer powders in a fluidized bed coupled to a cold remote plasma

In this work silicon oxide has been deposited from silane on fluidized polyethylene powders placed in a far cold remote nitrogen/oxygen plasma. The process temperature remained below 100 °C. The influence on the powder wettability of several key parameters such as the amount of oxygen injected in the plasma, the SiH4 flow rate and the treatment duration has been studied. From hydrophobic, the polyethylene powder wettability can be drastically improved depending on process conditions. Based on surface analyses of treated powders under various processing conditions, a deposition mechanism has been proposed combining homogeneous and heterogeneous nucleation and growth phenomena. The observed wettability variations appear to be linked to the surface coverage of the powder by the deposit.