Nobuyuki Zettsu, et al. Surface and Coatings Technology, 2008, 202(22-23), 5284-5288.
To improve the surface inertness of polytetrafluoroethylene (PTFE), this work demonstrates a strategy for bundled copper (Cu) metallization on PTFE surfaces by atmospheric pressure plasma liquid deposition (APPLD) technique to design interfaces for high-frequency electronic devices.
APPLD treatment for PTFE sheets
· The process proposed for surface functionalization through APPLD treatment consists of three main steps: first, modifying the PTFE surface to make it hydrophilic using a plasma-chemical treatment with atmospheric pressure helium (He) plasma for a short period; second, depositing an ultrathin film from a solution containing both P4VP and CuAc (P4VP/CuAc) onto the hydrophilically modified PTFE surface; and third, using plasma assistance to reduce Cu2+ ions to Cu(0) on the P4VP/CuAc-coated PTFE surface.
· The hydrophilic nature of the PTFE surface was significantly improved by the atmospheric pressure He plasma treatment under mild conditions. Remarkably, the spin-coated layer was firmly attached to the hydrophilically modified PTFE surface without any additional treatments, which can be attributed to the CASING mechanism. Exposure of the P4VP/CuAc-covered PTFE film to atmospheric pressure He plasma effectively converted Cu2+ ions to Cu(0), creating Cu(0) seeds.
· Initial findings suggest that the plasma-assisted deposition of Cu(0) seeds could directly facilitate the initiation of electroless copper deposition without the need for extra surface activation steps like SnCl2 sensitization.
