Hybridization of the polymer multi-layer (PML) deposition process

Abstract

The polymer multi-layer (PML) process for the flash evaporation, condensation, and radiation curing of reactive fluids has been modified. The radiation curing step has been eliminated. Polymerization is accomplished by passing the monomer gas through a glow discharge zone, under forced flow conditions, prior to condensation on the substrate [1,2]. This hybrid process produces high rate deposition of solid films from high molecular weight/low vapor pressure liquid, or even solid, monomer precursors. The gas resulting from the flash evaporation of a liquid monomer mixture, or from a suspension of liquid monomer and insoluble solid particles, is used as the support medium for a glow discharge in a plasma polymerization/plasma enhanced chemical vapor deposition-like (PECVD) process. Due to the high molecular weight/low vapor pressure nature of the precursors, the plasma of the flash evaporated gas cryo-condenses at an extremely high rate on substrates at ambient, and higher, temperatures. Upon condensation the liquefied plasma immediately begins to polymerize to form a solid film due to the high concentration of radicals and ions contained in the liquid film. The process has been successfully implemented in a vacuum roll coating system in a roll-to-roll deposition process. Forced flow conditions serve to reduce homogeneous reactions in the gas phase which, in turn, prevents particle formation in the gas phase. A variety of polymer, and polymer composite, films have been deposited by this process ranging in thickness from 100 nm to 24 000 nm at web speeds as high as 96 linear meters per minute with excellent thickness uniformity [1,2]. This new deposition process will be discussed along with some properties of the films fabricated with this new process.