HYDROPHOBIC POLYMER-FILMS PLASMA-POLYMERIZED FROM CF4 HYDROCARBON AND HEXAFLUROACETONE HYDROCARBON MIXTURES

Polymer films were deposited from the plasma polymerization of the mixtures of hydrocarbons, ethane, ethylene, and acetylene, and tetrafluoromethane (CF4) or hexafluoroacetone (HFA). The surface properties, the advancing contact angle of water, and surface energy of the films deposited and the chemical composition at the outermost layer of the films are discussed from the data of the angular XPS measurements. The plasma polymers deposited from the CF4/hydrocarbon and HFA/hydrocarbon mixtures contained fluorine atoms whose content depended on the CF4 or HFA concentration of the mixtures. The hydrophobicity of the films deposited could not be determined by the fluorine content of the films but by the chemical composition of the fluorine moieties at the outermost layer of the films. The CF3 moieties rather than the CF2 and CF moieties contribute largely to the hydrophobicity of the films. The plasma polymer films deposited from the HFA/acetylene (87.5 mol % HFA) showed higher hydrophobicity (the surface energy is 9.7 mJ/m2) than those from the CF4/acetylene mixture (87.5 mol % CF4) (the surface energy is 13 mJ/m2).