Early Stages of Growth of Plasma Polymer Coatings Deposited from Nitrogen- and Oxygen-Containing Monomers

Ultrathin functional coatings deposited by plasma polymerization have utility in nano- and microtechnologies, however, until now very little has been reported to validate the widely held view that these coatings can be deposited onto any type of substrate, without substrate influence. In order to ascertain the role of the substrate in the early stages of plasma growth we address the growth rate and chemistry of plasma polymer coatings from two nitrogen- and two oxygen-containing monomers during the first stages of deposition onto gold and onto thiol MUA-coated gold surfaces. SPR thickness measurements and XPS analyzes indicate the substrate must be taken into account when ultrathin plasma polymer coatings are used for surface modification and we speculate on why this should be so. Substratum chemistry influences both the rate of plasma polymer deposition and the chemistry of the deposit in the first few nanometers of film growth. Film growth rate is measured in a uniquely designed SPR experiment on gold and thiol-coated gold surfaces. Surface chemistry is measured by XPS.