Cold Plasma Surface Modification of PLA and LDPE Polymer Plastics

Low-density polyethylene (LDPE) and polylactic acid (PLA) plastic films were subjected to modification using different plasma sources. Argon, nitrogen, air and oxygen were used as a gas phase throughout the process, and their impact on the material's surface properties was verified. The surface activation rate was measured via atomic force microscopy regarding the porosity factor and using the water contact angle technique. The last method - being feasible, agile and of high sensitivity to alternating physicochemical surface character - was utilised to verify the post-process stability of the modified surface. Those tests were performed extensively, up to 160 hours (contact angle) and 240 hours (atomic force microscopy).