Preparation of hydrophilic plasma-polymers derived from oxygen-containing organic monomers

Abstract

Plasma polymerization of nine oxygen-containing organic monomers was surveyed for producing hydrophilic films on solid substrates on due consideration of chemical structures of the monomers, operative conditions for plasma polymerization, and resultant film characters. The wettability of the polymer films were evaluated by measuring the contact angles of water on the film surfaces while the power consumption was compared as the lowest wattage needed for sustaining normal deposition rates of the polymer films. It has been found that the monomers involving the triple bond in the chemical structure conducted plasma polymerization under very low wattage of radiofrequency power, and at the same time the deposition rate was relatively high. With respect to the chemical structures of the monomers, the hydroxyl group tended to initiate and sustain the electric discharge at somewhat lower power than other functional groups. Highly hydrophilic polymer films could, thus, be obtained under a soft plasma condition by using propargyl alcohol (2-propyn-1-ol) as a monomer having the triple bond and the hydroxyl group. X-Ray photoelectron spectra of the polymers suggested that the wettability was not simply dependent upon oxygen atom content of the polymers, but also dependent upon spatial arrangement of the oxygen atoms within the polymer molecules. © 1996 John Wiley & Sons, Inc.