Evolution of Hydrophobicity in Plasma Polymerised 1,7-Octadiene Films

1,7-Octadiene (OD) was plasma polymerised onto silicon wafers and glass slides under a broad range of input specific energies and deposition times to study the hydrophobicity of deposited films. Deposition of plasma polymerised 1,7-octadiene (ppOD) film resulted in decrease of glass slide surface free energy (SFE) from approximate to 71 to 44mJm(-2). X-ray photoelectron spectroscopy (XPS) and time of flight secondary ion mass spectroscopy (ToF-SIMS) results confirmed that this decrease is due to the concealing of polar SiOH groups by non-polar CxHy functionalities. Atomic force microscopy (AFM) images along with ToF-SIMS spectra suggested patchy-like growth of ppOD films in the very early stages of polymerisation. It has been demonstrated that a precise control over the surface hydrophobicity is achieved by simply tuning the plasma polymerisation parameters.