Abstract
•Oxygen reactive ion etching is a commonly used method in micro-mechanical fabrication process. In the manuscript, this processing method is optimized to modify the internal surface of parylene-C. The proposed method is completely compatible with the fabrication process of a PC based electrode.•A layer of nano-wire array with proper size and density (“nano-forest”) fabricated on the bottom PC can enhance its adhesion with both metal and top PC layer on it. The proposed method is simple.•Compared with commonly used chemical adhesion promoter (saline A-174 for example), the proposed method is more biocompatible.•The sealing property or the anti-permeability at interface of bottom/top PC layer is improved.•The reliability of a PC based implantable electrode can be improved by this method.
Parylene-C (PC) is one of the most frequently used materials for flexible implantable electrode. Its interface with metal or other PC layer is critical in PC–metal-PC “sandwich” implantable neural electrodes in relation to their long-term reliability. In this study, we aim to develop a method to improve metal-PC and PC–PC adhesion in PC-based neural electrodes. “Nano-forest” structure, composed of nanopillar array is fabricated on the surface of bottom PC by oxygen reactive ion etching (RIE). The contribution of this layer of nano-structure to mechanical adhesion and sealing property are evaluated respectively. The results verify that for PC based “sandwich” electrode, not only the mechanical adhesion among three layers, but also the sealing ability between PC layers are significantly improved.