Apparatus for indirect atmospheric pressure plasma processing

Abstract

Apparatus for plasma processing of a continuous fiber, comprising a first and a second plasma torch. Each plasma torch comprises oppositely arranged electrodes to define a plasma discharge chamber between the electrodes. The plasma discharge chamber comprises an inlet and an outlet for passing a plasma forming gas between the electrodes. The apparatus further comprises an afterglow chamber in fluid communication with the outlets of the plasma discharge chambers, which comprises a substrate inlet and a substrate outlet arranged at opposite sides of the outlets of the plasma discharge chambers. A transport system is configured to continuously transport the fiber from the substrate inlet to the substrate outlet through the afterglow chamber. The substrate inlet comprises an aperture having a cross-sectional size substantially smaller than a cross-sectional size of the afterglow chamber. The outlets of the plasma torches face each other and exhaust plasma activated species into the afterglow chamber.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims priority to European Patent Application No. 15191844.8, filed Oct. 28, 2015, which is hereby incorporation by reference.FIELD OF THE INVENTION[0002]The present invention is related to apparatuses and methods for indirect atmospheric pressure plasma processing, in particular where the substrate to be plasma processed is kept remote from the plasma discharge zone.[0003]With indirect or remote plasma treatment of substrates, as opposed to in-situ plasma treatment, the substrate is not passed through the plasma discharge zone, in which an atmospheric pressure plasma is maintained between electrodes and activated species are formed. Instead, the substrate is positioned at a location remote from the plasma discharge zone and the plasma-activated species are transported to the remote location where they are made to react with the substrate. Remote plasma treatment is often preferred over in-situ treatment, in particular fo...

AI Technical Summary

Benefits of technology

The present invention aims to improve uniform and homogeneous plasma processing of a substrate surface, particularly for non-oxidative plasma treatments. This is achieved by reducing the aperture of an afterglow chamber at the substrate inlet, which allows the afterglow zone to propagate further downstream along a transport direction of the substrate, resulting in increased plasma treatment efficiency. Additionally, the invention provides a second plasma torch that can provide a more intense afterglow stream, allowing for uniform treating continuous fibers along 360° of the circumference.

Problems solved by technology

The resulting superimposition of high drift velocity in the process gas flow and the inherent diffusion movement results in a prolonged displacement distance of activated species into the treatment zone.

A drawback of the above apparatus is that the concentration of plasma activated species in the treatment zone is not uniform in a radial direction.

A drawback of the above apparatus is that the surface activation of the PAN fiber is low due to air entrained with the PAN fiber.

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