| AVS 55th International Symposium & Exhibition | |
| Advanced Surface Engineering | Wednesday Sessions |
| Session SE-WeM |
| Session: | Atmospheric Pressure Treatments and Hard and Nanocomposite Coatings |
| Presenter: | L. O'Neill, Dow Corning, Ireland |
| Authors: | L. O'Neill, Dow Corning, Ireland J.D. Albaugh, Dow Corning, Ireland |
| Correspondent: | Click to Email |
Recent studies have clearly demonstrated that numerous precursors can be used to produce thin film coatings by injecting liquid aerosol droplets into a non-thermal equilibrium atmospheric pressure plasma. The deposition appears to proceed via a controlled free radical polymerisation with controlled precursor fragmentation. It has recently been reported that several different siloxane products and intermediates can be used to prepare thin films by this method and the resultant coatings can be tailored to produce deposits which vary from hydrophobic siloxane to cross-linked silica thin films. Linear, cyclic, dimethyl and Si-H containing siloxanes have been deposited with equally high deposition rates. However, under certain conditions, coatings deposited from linear and dimethyl structures can appear "wet" and have a presumably low cross-link density compared to their cyclic or Si-H counterparts. Therefore, a more detailed study has been undertaken to investigate which factors control deposition rate and cross-link density in liquid aerosol – plasma polymerisation processes. A series of liquids have been nebulised and introduced into a purpose built RF atmospheric pressure plasma jet operating with helium as the main process gas. The resultant coatings have been thoroughly characterised to determine which chemical properties of the precursor directly impact upon the chemistry and morphology of the coatings.