Abstract:There is much scientific and commercial interest in plasma polymers to modify surface chemistry. To date, only neutral and positively charged species have been detected in the commonly applied acrylic acid plasma. Using time-averaged negative ion mass spectrometry, we demonstrate that large, negatively charged species exist in the plasma, contrary to previous studies that detected only neutral and positive species. We briefly outline how negative molecules may contribute to the deposition of plasma polymer in … Show more
“…Over the last 30 years many techniques have been developed and used to modify the surfaces of many different polymers. Corona discharge, plasma treatment, plasma polymerization, grafting copolymerization and UV/treatment with ozone have all achieved successful results. Contrary to other methodologies, UV‐assisted treatment is mainly based on photo‐induced chemical processes, where special photoreactive moieties (which can be either side groups or part of the main chain of the macromolecule) have a distinct, selective and efficient reactivity.…”
“…Over the last 30 years many techniques have been developed and used to modify the surfaces of many different polymers. Corona discharge, plasma treatment, plasma polymerization, grafting copolymerization and UV/treatment with ozone have all achieved successful results. Contrary to other methodologies, UV‐assisted treatment is mainly based on photo‐induced chemical processes, where special photoreactive moieties (which can be either side groups or part of the main chain of the macromolecule) have a distinct, selective and efficient reactivity.…”
“…In this manuscript we expand upon this preliminary report and present a more comprehensive investigation of the deposition rate and chemical composition of nitrogen (amine)‐ and oxygen (carboxyl)‐containing monomers on metal (gold) and organic (MUA) surfaces. Amine‐ and carboxyl‐containing monomers were selected for two reasons: Firstly, these monomers are precursors for creating coatings of controlled functional group density, which have been employed in a wide range of applications;15, 33, 35, 36, 41–43 secondly, there is a significant body of work describing aspects of the polymerization of these monomers,44–53 by reference to which we are able to formulate a working hypothesis that helps in understanding the substrate differences we report.…”
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.
“…Traces of the reactions of such a type with elimination of H 2 O or C 2 H 2 at the plasma polymerization of acrylic acid were detected by means of a negative ions mass spectrometry 22. Plasma polymerization is quite another phenomenon than the classical chemical polymerization.…”
Kinetic pictures, i.e., full sets of all available kinetic curves, were obtained with the help of continuous mass spectrometry and analyzed with the purpose of studying some aspects of the mechanism of initial stages of molecular growth in a batch reactor. The kinetic curves were clearly parted into three types—initial, intermediate, and final. All of the new substances are evolving simultaneously and in parallel, independently of their molecular mass, from C2 to C18, what evidences that the fast stepwise or chain reactions of chemical synthesis are preceded by the slow limiting stage of the discharge activation. The method of momentary characteristics is demonstrated which allows to perform a quantitative analysis of the kinetic material even in the difficult cases of batch and modulated systems.
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