Understanding the chronic immune response to implanted neural electrodes is important from both a patient safety and long-term device functionality standpoint.  In this investigation, we focused on examining the effects of the chronic immune response on the long-term functionality of µECoG surface electrodes implanted under the dura matter of in vivo rat models over a period of six weeks.  We characterized the abio-bio interface of the explanted devices, and compared the biological layer adhered to capacitive (glassy carbon) electrodes to that of faradaic (Pt) electrodes.  In addition, in vitro electrical conductivity tests of the explanted devices were performed, and the results were compared to both previously recorded pre-implant and in vivo conductivity data.  Subsequently, the overall corrosion of the capacitive and faradaic electrodes were compared.  Because both electrode types were coated in the same insulating material (polyimide) formed in the same geometry, the differences in the chronic immune response to the implanted devices can be attributed to the presence of either capacitive or faradaic electrodes.  Further, we support the experimental observation with finite element modeling of the electrode/tissue interface where electric field, Nernst-Planck diffusion of charges, double layer capacitance, and pH distribution are evaluated qualitatively and quantitatively and correlated with experimental results.