The role of ions in the plasma polymerization of allylamine

The radio-frequency-induced plasma polymerization of allylamine has been in vestigated in the plasma-gas phase by mass spectrometry and at the plasma-s olid interface by means of an ion flux probe and a quartz mass balance. The surface chemistry of the deposits has been determined by X-ray photoelectr on spectroscopy. The objective of this study was to unravel the mechanism(s ) by which allylamine plasma polymers form. The results are compared with t hose obtained in an earlier investigation of the plasma polymerization of a crylic acid. In the plasma-gas phase, evidence is provided for reactions: b etween cations and intact neutral monomers (allylamine). These oligomerizat ion reactions were found to be relatively power-insensitive compared with t hose seen in plasmas of acrylic acid, as was the gas-phase concentration of the intact neutral monomer. At the polymer surface, ion fluxes were found to increase with plasma input power (P) from 6.6 x 10(16) ions m(-2) s(-1) at 1 W to 1.4 x 10(18) ions m(-2) s(-1) at 14 W. The ionic mass transport t o the polymer surface lion mass flux) was calculated by multiplying the mea sured ion flux by the average ion mass (determined by mass spectrometry). A t P = 1 W, the ion mass flux was 11.7 mum m(-2) s(-1), and at 14 W, the ion mass flux was 226.6 mum m(-2) s(-1). These values differed from the total mass deposition rates measured by the quartz mass balance, which were 18.7 and 127.1 mum m(-2) s(-1), respectively. However, the relationship found be tween the ion mass flux, the mass deposition rate, and P was complex, and i t is shown that, at very low P (<1 W), the ion mass flux is sufficient to a ccount for all of the deposit.