Highly conductive flexible printed patterns based on magnetic core-shell copper-coated-nickel nanoparticles catalyzing dimethylamine borane electroless plating copper

Abstract

In this work, we demonstrate the catalytic application of magnetic core-shell copper-coated-nickel (Ni@Cu) nanoparticles (NPs) for dimethylamine borane (DMAB) reduced electroless plating copper to fabricate flexible, highly conductive copper patterns. The Ni@Cu NPs, with size of 40 to 46 nm and saturation magnetization of 9.13 emu/g, exhibited strong magnetism, which can be separated by a magnet. Furthermore, the NPs possessed superparamagetism, which meant that the NPs could quickly redisperse in a solvent once the external magnetic field was removed. The core-shell structure of Ni@Cu NPs offered distinct advantages: the nickel core facilitated straightforward magnetic separation, while the copper shell ensured effective dispersion and robust catalytic activity. As the catalyst seeds for electroless plating copper, the Ni@Cu NPs exhibited superior catalytic activity for preparing conductive, adhesive, antioxidative, and bendable flexible copper patterns. The resistivity of the obtained conductive copper patterns was quite low, approximately 1.2 times that of bulk copper. The surface of the copper patterns was smooth, with a relative roughness of 2.67 %, and remained stable under 2000 cycles bending test and 50 cycles 3 M tape test, without any increase in sheet resistance or detachment of the conductive coating. The results of this research will provide new perspectives and basics for the low-cost and large-scale preparation of flexible printed circuits, and will promote the development of the flexible electronics industry towards high efficiency and environmental friendliness.