Adhesive properties of polyester treated by cold plasma in oxygen and nitrogen atmospheres

Polyester foil was treated by the surface diffuse barrier discharge (SDBD) plasma at atmospheric pressure in oxygen and/or in nitrogen containing a small amount of oxygen to improve its surface and adhesive properties. Changes in a chemical structure of the polyester were analyzed by electron spin resonance (ESR) spectroscopy, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and by X-ray photoelectron spectroscopy (XPS). The changes in surface morphology were studied using scanning electron microscopy (SEM) and atomic force microscopy (AFM). A surface energy as well as an adhesion of polyester modified by the SDBD plasma to polyacrylate significantly increased. The efficiency of the modification by the SDBD plasma depends on the used processing gas as well as on the modification time. The decrease in the surface energy of polyester modified by the SDBD plasma due to hydrophobic recovery was also investigated. A correlation between adhesive properties of polyester modified by the SDBD plasma and its surface has been found.