Metallization of Polyphenylene Sulfide by Low-Cost Mussel-Inspired Catechol/Polyamine Surface Modification

An economical and efficient strategy for fabricating high-performance metallic copper layers on polyphenylene sulfide (PPS) for high-frequency microwave applications via mussel-inspired surface modification and electroless copper plating (ECP) is illustrated in this paper. Through UV-induced surface modification of catechol (CA)/polyamine (PA), the modified PPS substrate is capable of adsorbing silver particles, which provides activation sites for subsequent ECP. The impact of CA/PA modification on the relationship between PPS and the deposited copper layer can be determined by water contact angle measurements, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and tape peel tests. The involvement of CA/PA has successfully introduced the functional groups for chemical bonding on the PPS surface, which greatly improves the adhesion between the PPS and the deposited copper layer. Moreover, after 40 min of ECP, the produced copper layer exhibits good adhesion at the 5B level (according to the ASTM D3559) and an excellent conductivity of 0.37 S/m (approx. 62% of bulk copper). Meanwhile, the deposited copper layer also has good resistance to acid, alkali, and salt corrosion (less than 25 g/m2 per unit area weight loss after 60 h of corrosion). This approach opens up an efficient path for the surface metallization of PPS, which has a broad potential for application in high-frequency copper-clad laminates (CCLs).