Comparison of Low- and Atmospheric-Pressure Radio Frequency Plasma Treatments on the Surface Modification of Poly(methyl methacrylate) Plates

In this article, the effects of RF (radio frequency) atmospheric pressure plasma (APP), and low pressure plasma (LPP) treatment were compared on the surface of the poly(methyl methacrylate) (PMMA) plate. The APP was proved to be able to improve the surface free energy of the PMMA faster and higher than the LPP under similar treatment condition. Atomic force microscopy revealed extraordinary surface roughness and morphology generated only on the APP-treated PMMA, where the cracks appeared. The surface temperature increased very quickly and exceeded quickly the glass transition temperature ( T g ) of PMMA on the APP-treated surface, while it showed a little increase below the T g on the LPP-treated surface. X-ray photoelectron spectroscopy analysis revealed a novel reaction mechanism is proposed for the formation of the nitrogen-containing groups. It was believed that the generation of new oxygen- and nitrogen-containing groups was dependent on the plasma treatment environment, which provided necessary active species for the formation of the new functional groups.