Controlled chemical and morphological surface modifications via pulsed plasma polymerizations: Synthesis of ultrahydrophobic surfaces

The RF plasma polymerization of saturated linear and cyclic perfluoroalkane monomers and vinyl acetic acid were studied in this dissertation. Film chemical compositions, deposition rates, surface wettabilities and morphologies were characterized as functions of various plasma processing conditions. Large progressive changes in chemical compositions with sequential variations in plasma duty cycle were demonstrated in polymerization of both perfluoroalkane and vinyl acetic acid monomers.; As anticipated, polymer films obtained from the perfluorocarbon monomers exhibited a general trend towards more linear structures with decreasing plasma duty cycles. However, completely unexpectedly, ultrahydrophobic films were obtained from some of these monomers under restricted duty cycle and power input conditions. SEM and XPS characterizations revealed that a rough, fibrous-like surface morphology is responsible for this ultrahydrophobicity, as opposed to unusual chemical compositions. The growth of the fibrous surface is believed to arise from nucleation and hillock-like growth patterns on selectively activated sites of the growing polymer film. Surface mobility of plasma generated reactive species apparently plays an important role in the growth of the fibrous ultrahydrophobic surfaces, as shown by substrate temperature studies. Additionally, the present study revealed a number of interesting new observations of significant differences in the chemical compositions and deposition rates of polymer films obtained from the diverse range of perfluorocarbon monomers employed in this work.; The ultrahydrophobic fluorocarbon films discovered in this investigation were evaluated for use in several biomaterial applications. The results obtained show excellent marine antifouling properties for these surfaces, as documented in ocean testing experiments. These surfaces have also been shown to be useful in controlling protein and peptide surface adsorptions, as well as in the inflammatory response of live tissue to implants.; The pulsed plasma polymerization of vinyl acetic acid was demonstrated to be a convenient route to tailoring surfaces with controllable surface densities of COOH groups. It was shown that these surfaces can be effectively employed as ion permselective membrane and for use as substrates in MALDI-MS analysis of peptides. Results obtained are interpreted in terms of the presence of a negative surface charge on these surfaces when immersed in aqueous solution at neutral pH.