Functionalised Copper Nanoparticle Catalysts for Electroless Copper Plating on Textiles

Electroless copper plating can be regarded as an enabling technology for electronic textiles, however, the choice of catalyst is critical. In this study, electroless copper plating of a polyester textile was performed using catalysts including a palladium/tin colloid and catalysts based on silver and copper nanoparticles (CuNPs). These CuNPs were functionalised using different ligands including (3-Aminopropyl)triethoxysilane (APTS), oleic acid (OA) and polyacrylic acid (PAA). The catalysts were characterised using Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS) and X-ray Photoelectron Spectroscopy (XPS). The efficacy of different catalysts was determined by characterising electroless copper plated textiles in terms of mass gain (after plating), the coatings coverage and deposits morphology using Scanning Electron Microscopy (SEM). In addition, the sheet resistance of the plated textiles was measured using a four-point probe. The results revealed the important role of functionalising molecules on the performance of CuNPs as a catalyst. The overall best performing CuNP catalyst was CuNP-PAA which had Cu (I) species and the most dispersed and smallest particles. The amount of Cu (I) present in the catalyst, although low (1.7 at. %) seemed critical to the catalyst’s efficacy and its ability to produce a smooth and complete electroless copper coating with a very high conductivity.