TY - JOUR
T1 - Flexible nerve stimulation electrode with iridium oxide sputtered on liquid crystal polymer
AU - Wang, Kevin
AU - Liu, Chung Chiun
AU - Durand, Dominique M.
PY - 2009/1
Y1 - 2009/1
N2 - Current electrode designs require flexible substrates that absorb little moisture and provide large charge injection capability. Sputtered iridium oxide films have superior charge injection capabilities versus noble metals and can adhere to various substrates. Liquid crystal polymers (LCPs) have very little water absorption compared to other flexible substrates. Therefore, the combination of sputtered iridium oxide film on LCP substrate was studied using 50 Hz, 100 μs duration, and 10 mA biphasic current waveforms for 700 h at 67°C in bicarbonate buffer saline. Scanning electron micrograph analysis showed no delamination and approximately 1% of electrode material was lost to the bicarbonate buffer. The charge injection limit and the cathodic charge storage capacity within the water window were 4.6 ± 1.0 and 31.5 ±6.6 mC/cm2, respectively. Additional electrochemical analysis revealed significant charge imbalance attributed to oxygen reduction within the water window. These results, along with the flexible, chemically inert, and biocompatible substrate, indicate that sputtered iridium oxide films on LCP could become the method of choice for flexible substrate nerve electrodes.
AB - Current electrode designs require flexible substrates that absorb little moisture and provide large charge injection capability. Sputtered iridium oxide films have superior charge injection capabilities versus noble metals and can adhere to various substrates. Liquid crystal polymers (LCPs) have very little water absorption compared to other flexible substrates. Therefore, the combination of sputtered iridium oxide film on LCP substrate was studied using 50 Hz, 100 μs duration, and 10 mA biphasic current waveforms for 700 h at 67°C in bicarbonate buffer saline. Scanning electron micrograph analysis showed no delamination and approximately 1% of electrode material was lost to the bicarbonate buffer. The charge injection limit and the cathodic charge storage capacity within the water window were 4.6 ± 1.0 and 31.5 ±6.6 mC/cm2, respectively. Additional electrochemical analysis revealed significant charge imbalance attributed to oxygen reduction within the water window. These results, along with the flexible, chemically inert, and biocompatible substrate, indicate that sputtered iridium oxide films on LCP could become the method of choice for flexible substrate nerve electrodes.
KW - Delamination
KW - Electrochemical testing
KW - Iridium oxide
KW - Liquid crystal polymer (LCP)
KW - Oxygen reduction
UR - http://www.scopus.com/inward/record.url?scp=60549105071&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=60549105071&partnerID=8YFLogxK
U2 - 10.1109/TBME.2008.926691
DO - 10.1109/TBME.2008.926691
M3 - Article
C2 - 19224713
AN - SCOPUS:60549105071
VL - 56
SP - 6
EP - 14
JO - IEEE Transactions on Biomedical Engineering
JF - IEEE Transactions on Biomedical Engineering
SN - 0018-9294
IS - 1
ER -