Glass bond adhesive strength improvement by DCSBD atmospheric-pressure plasma treatment

A novel type of dielectric barrier discharge, the so called Diffuse Coplanar Surface Barrier Discharge (DCSBD), has been used for the treatment of glass surfaces prior to their bonding with a UV-curing acrylate adhesive. The DCSBD is a source of diffuse, atmospheric-pressure “cold” plasma with power densities reaching ~ 100 W/cm3 even in strong electronegative gases (e.g. pure oxygen) without any admixture of helium or argon. The plasma is generated in a thin, ~ 0.5 mm thick layer suitable for the treatment of flat materials like glass or polymeric foils. The plasma treatment of glass results in an overall decrease in organic contamination of the surface and, possibly, in an increase in the surface density of –OH groups promoting reactions on the glass surface, both effects being beneficial for adhesive properties of the glass surface. Plasma treated adhesive joints have been subjected to mechanical testing according to the ISO 4587 standard. Results indicate more than 45% improvement in the plasma treated joints adhesive strength, when compared to the untreated reference joints. Moreover, the different cleaning protocols used indicate, that it will be possible to substitute distilled water instead of ethanol in the cleaning procedure, which is a rather expensive and hazardous chemical.