PEKK (polyether-ketone-ketone) polymer has been actively studied in applying electronic devices in satellites owing to its excellent light weight and thermal resistance. However, the limitation of metal coating to form on the PEKK surface is due to the high-volume resistivity and surface resistance. Here, we have investigated the correlations between the chemical treatment of the surface and adhesion strength between polymer–metal coating. Three-dimensional printed PEKK objects were manufactured and nickel was deposited on the surface by electroless plating. As the concentration of H₂SO₄ increased from 12.5 to 14.3 mol/L, the pore diameter showed a tendency to increase. However, as growing pore induced connecting each other, the pore size re-decreased from 15.1 to 18.0 mol/L. To control pore size and uniformity, we investigated the pore diameter of 3D printed PEKK as a function of treatment time and temperature. Uniform pores were observed at a temperature of 50 °C which were formed after 10 min and the average pore size was 0.28 μm. After H₂SO₄ swelling, samples were re-treated in the KMnO₄-H₃PO₄ etching system for the hydrophilic group. KMnO₄ broken C=C bonding and generated hydrophilic groups such as -COOH and -OH, the contact angle decreased from 64.7 to 51.1° compared with H₂SO₄ swelling. XPS survey spectra confirmed that not only breaking C=C bonding but also increasing hydrophilicity due to -OH, -C-, -SO3 and the catalyst absorption of Pd was improved. As a result of adhesive strength by ASTM D3359, compared with the H₂SO₄ swelling, the KMnO₄-H₃PO₄ etching system showed 5B which is the best result in standard test methods by adhesive tape test and peeling amount on the tape was less than 0.01%.

In this study, we verified the relationship among the electrical conductivity, chemical durability, and structure of conductive vanadate glass in which BO 3 and BO 4 and V 4+ and V 5+ coexist simultaneously. We prepared samples of vanadium borophosphate glass with various compositions, given by 50V 2 O 5-xB 2 O 3-(50-x)P 2 O 5 (x = 0 ~20 mol%) and 70V 2 O 5-xB 2 O 3-(70-x)P 2 O 5 (x = 0 ~10 mol%), and analyzed the electrical conductivity, chemical durability, FT-IR spectroscopy, thermal properties, density, and molar volume. Substituting B 2 O 3 for P 2 O 5 was found to improve the electrical conductivity, chemical durability, and thermal properties. From these results, we can draw the following conclusions. First, the electrons shift from the electron rich V 4+ to the electron deficient BO 3 as the B 2 O 3 content increases. Second, the improvement in chemical durability and thermal properties is attributed to an increase in cross-linked structures by changing from a BO 3 structure to a BO 4 structure.