Photo-initiated chemical vapor deposition of thin films using syngas for the functionalization of surfaces at room temperature and near-atmospheric pressure

Abstract

Hydrophilic and hydrophobic thin films have been deposited onto flat metallic substrates through photo-initiated chemical vapor deposition (PICVD), using syngas as a precursor, and affordable UVC germicidal lamps as a source of light. This study is the first experimental investigation of what has been previously concluded to be the potential solution to the current widespread nanoparticle functionalization problem. This study addresses the current limiting factor, namely the cost issue, by using simple gas precursors, using an affordable initiation source and operating under normal conditions. This approach differs from the current approaches which use expensive solvents as precursors, energy consuming-sources of initiation (e.g. high temperature, plasma and VUV) and operate under high vacuum and/or high temperatures. While the current paradigm is to target the peak absorption of a molecule, the present study indicates that long chain polymerized products can be formed from off-peak wavelengths. It has been found that photo-initiated deposition occurs and that a wide range of water contact angles, from 5° to 118°, can be obtained by manipulating the experimental conditions. A multilinear empirical model has been derived, and it predicts fairly well the contact angles obtained as a function of the different experimental parameters.