Laser-assisted metallization of composite coatings containing copper(II) acetylacetonate and copper(II) oxide or copper(II) hydroxide

This article presents the results of laser-assisted metallization of polyurethane coatings containing 5 wt.% of Cu(acac)2 and 15 wt.% of copper(II) oxide (CuO) or copper(II) hydroxide (Cu(OH)2). Thus, two different coating compositions were compared with regard to becoming active after laser irradiation for direct electroless metallization. Coatings were irradiated with ArF excimer laser using various numbers of laser pulses at a constant fluence of 100 mJ/cm2, and then electroless metallized with copper. Surface properties resulting from laser irradiation were evaluated mainly based on surface morphology, chemical alterations and general optical assessment of deposited copper layers. It was evaluated using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and optical imaging. It was found that surface layer of the coatings containing Cu(OH)2 could be activated, and thus copper plated at lower energy dose of laser radiation as compared to the coatings containing CuO. It resulted from more efficient laser ablation and formation of metallic copper on the coating surface. Empirical model for the change of copper content resulting from laser radiation and practical conclusions on the applicability of the coatings is presented in this work.