Large area, atmospheric pressure plasma for downstream processing

摘要

An arcless, atmospheric-pressure plasma generating apparatus capable of producing a large-area, temperature-controlled, stable discharge at power densities between about 0.1 W/cm3 and about 200 W/cm3, while having an operating gas temperature of less than 50° C., for processing materials outside of the discharge, is described. The apparatus produces active chemical species, including gaseous metastables and radicals which may be used for polymerization (either free radical-induced or through dehydrogenation-based polymerization), surface cleaning and modification, etching, adhesion promotion, and sterilization, as examples. The invention may include either a cooled rf-driven electrode or a cooled ground electrode, or two cooled electrodes, wherein active components of the plasma may be directed out of the plasma and onto an external workpiece without simultaneously exposing a material to the electrical influence or ionic components of the plasma.

主权项

1. An atmospheric-pressure plasma discharge apparatus comprising in combination:
a first electrode having a cylindrical inner surface and a first axis of symmetry; a plurality of parallel tubes forming a second cylindrical electrode interior to said first electrode and having a second axis of symmetry co-axial with the first axis of symmetry, each tube of said plurality of tubes having an outer surface spaced apart a first chosen distance from the inner cylindrical surface of said first electrode, the outer surface of each tube of said plurality of tubes further being spaced apart a second chosen distance from the outer surface of an adjacent tube thereto; an rf power supply in electrical contact with either of said first electrode or each tube of said plurality of tubes for providing rf power to said first electrode or said second electrode, the unpowered electrode of said first electrode or each tube of said plurality of tubes being placed in electrical contact with a ground electrical potential;
means for cooling each tube of said plurality of tubes to a chosen temperature; andmeans for flowing a gas into the annular space between said first electrode and said second electrode and out of the annular space between said first electrode and said second electrode between the spaced-apart outer surfaces of each tube of said plurality of tubes;whereby an atmospheric pressure plasma is generated between said first electrode and said second electrode.