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.