Study of silane-assisted electroplating techniques and applications

Abstract

In the traditional electrochemical industry, electroplating is a cost-effective and high-throughput process used in a wide range of applications such as electronics, printed circuit boards and semiconductors. However, because of its customised functionalised head and tail groups, silane is widely used as a coupling agent for resins and metal interfaces and as a corrosion inhibitor. In this study, we aimed to tackle two remaining important issues in the electroplating process with the assistance of silane. First, silane was used as a bridging link to deal with the poor surface coverage and interfacial adhesion between the electroplated metal and low surface-energy substrate, such as indium tin oxide polyethylene naphthalate (ITO-PEN). We used 3-mercaptopropyl-trimethoxysilane as an effective promoter to enable uniform electroplating of Ag on ITO-PEN with strong adhesion. The layer of 3-mercaptopropyl-trimethoxysilane on the substrate provided the bridging link between the sulphur functional groups and the Ag ions in the electrolyte, which facilitated the electroplating nucleation process. This cost-effective and reliable electroplated metallisation process would be applicable in manufacturing various metals on ITO-PEN that allows the devices to be flexible and rollable. Second, silane works as a potential dependent suppressor that can solve one of the great challenges in the fabrication of nanomaterials by electroplating, that is, to overcome the surface energy and prevent the nanostructures or nanomaterials from growing in size, driven by a reduction in the overall surface energy. We developed a new method of rapid electroplating Au nano-dendrites by adding (3-aminopropyl)trimethoxysilane (APTS) into the electrolyte in combination with the sweeping potential technique. The effect of APTS, the potential waveform and a growth mechanism were proposed. Finally, the effectiveness of Au nano-dendrites was demonstrated through applications such as a direct methanol fuel cell and a non-enzymatic glucose sensor.