Surface Modification of Tetrafluoroethylene−Perfluoroalkyl Vinyl Ether Copolymer (PFA) by Remote Hydrogen Plasma and Surface Metallization with Electroless Plating of Copper Metal

Effects of Polymer Architecture and Composition on the Adhesion of Poly(tetrafluoroethylene)

Poly(glycidyl methacrylate), PGMA, chains in linear and arborescent structures were incorporated onto surfaces of poly(tetrafluoroethylene), PTFE, films by hydrogen plasma and ozone treatment and atom transfer radical polymerization. The epoxide groups of the PGMA chains were further reacted with acetic acid (AAc), oxalic acid (XAc), allyl amine (AA), and ethylenediamine (EDN) to introduce hydroxyl and amine groups to the surfaces of the PTFE films. Surface characterizations performed by Fourier Transform infrared attenuated total reflectance (FTIR-ATR) spectroscopy and X-ray photoelectron spectroscopy (XPS) confirmed the surface modification and the chemical structure. The PGMA chains in arborescent structures show a high effectiveness for the enhancement of the adhesion of PTFE films. The adhesion of PTFE films was also significantly enhanced by ring-opening reactions of the PGMA epoxide groups with acetic acid and amine compounds. A high value of 9.5 N cm(-1) in the optimum 180 degrees peel strength test was observed with PTFE/copper assemblies.

Nonwetting process for achieving surface functionalization of chemically stable poly(tetrafluoroethylene)

Using a low-energy Ar+ ion-beam with and without a reactive gas, chemically stable poly(tetrafluoroethylene) (PTFE) films were modified to have special surface features. The adhesion strength between the PTFE and the copper was significantly improved because of both changes in the surface topography and chemical interactions due to PTFE functionalization (oxidation and amination). The surface modification altered the failure mode from adhesive failure for the unmodified PTFE/Cu interface to cohesive failure for the surface-modified PTFE/Cu layer interface.

Polyetheretherketone (PEEK) surface functionalization by low-energy ion-beam irradiation under a reactive O2 environment and its effect on the PEEK/copper adhesives

A low-energy Ar+ ion beam was used to modify the surface of a polyetheretherketone (PEEK) film. The modification reaction proceeded with or without oxygen gas injected during the irradiation. The surface functional groups of the modified PEEK were confirmed with X-ray photoelectron spectroscopy as increasing various oxygen-containing functional groups. The concentration of the functional groups varied rapidly with the irradiation time, reached a maximum value, and then slowly decreased. The surface morphology of PEEK was substantially changed by ion-beam irradiation. Surface smoothening occurred so that the surface roughness reached almost constant value after some irradiation time. The incorporation of functional groups on the PEEK surface and the surface topology change had opposite effects on the adhesion strength between PEEK and copper. Dominance of the former was evident because the lap-shear strength initially increased with the irradiation. The special surface features significantly enhanced the adhesion strength between the evaporated copper layer and the modified PEEK surface. However, the decrease in the surface roughness with a long time irradiation implies a decrease in adhesion strength due to a smaller contact area, and the shear strength due to topology change also slowly decreased after a long time irradiation.