| Abstract: | Plasma polymerization generates thin, pinhole-free, and highly adhering films and is often described by the ratio of power to mass flow rate (energy per mass). This research explores the relationships between plasma reactor parameters such as monomer flow rate, plasma power, and reactor pressure and the rates of polymerization, etching, and deposition. The chemical structure of the amorphous, crosslinked plasma polymerized hexafluoropropylene consists largely of similar amounts of C*-CF, CF, CF2, and CF3 groups and some C-C groups. A dimensionless plasma parameter (E) proportional to power and inversely proportional to flow rate cubed was derived. E, reflecting both plasma energy and residence time, was used to describe various aspects of the plasma reactions. A dimensionless exponential expression successfully described the dependence of pressure on E with a master curve. An expression for polymerization efficiency (polymer conversion) derived in part through a mass balance was also successfully related to E using an exponential master curve. The rate of deposition was described as the difference between the rates of polymerization and etching. The deposition efficiency maximum and plateau were successfully described by the difference between polymerization and etching efficiencies, each related exponentially to E. The technique used to derive parameters to describe the dependence of plasma reactions on plasma operating conditions can be applied to any monomer/reactor system. |
