Copper-Electroplating of Biodegradable PCL Nanofiber Mats

In this study, biodegradable polycaprolactone (PCL) nanofibers were copper (Cu) electroplated in a more environmentally friendly bath compared to conventional electroplating baths. The Cu-plating mechanism and determination of the optimum parameters for the production of Cu-plated PCL nanofiber mats were explained. PCL nanofibers were produced on metal frames by electrospinning. Cu-electroplating needs a conductive surface. To provide this, a gold/palladium (Au/Pd) mixing was sputtered on the PCL samples with different sputtering thicknesses (1-5-10-15 and 20 nm). After determining the minimum sputtering thickness as 5 nm, the samples were Cu-plated for 1, 3, 5, and 30 minutes in a citric acid electroplating bath. The surface properties of the samples were evaluated after Au/Pd sputtering and electroplating, respectively. Elemental analyses, mapping, and electrical characterizations were also performed after electroplating. After Au/Pd sputtering, the SEM images showed that randomly aligned nanofibers with an average diameter of 223 nm were produced. After electroplating, the average nanofiber diameters increased up to 444 nm. It was seen that the coating grew along the surface of the single nanofibers indicating a smooth Cu coating. While elemental analyses presented a Cu content of 79.77%, electrical characterizations gave a sheet resistance value of 5.98 m Omega/sq for the samples Cu-plated for 30 minutes, indicating a highly conductive structure. Every step of the study is described in detail to provide insight for further studies.