The Effect of Applied Waveform Type and Voltage Amplitude on Poly(3,4-ethylenedioxythiophene) (PEDOT) Polymerization
Authors: Jacob B. Chytil, Jamie M. Murbach, Kevin J. Otto PhD
Faculty Mentor: Kevin J. Otto PhD
College: Herbert Wertheim College of Engineering
A reliable neural interface is imperative to neuroprosthesis function and chronic durability. The conductive polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), has been shown to improve electrochemical properties for neural interfacing applications through reducing impedance magnitude across all frequencies and increasing charge storage capacity and charge injection capacity for both recording and stimulation[1,2]. The goal of this study was to evaluate the effect of applied waveform type and voltage amplitude on PEDOT polymerization in vitro. Insight into how these electrical parameters affect PEDOT polymerization can help improve chronic function of the device-tissue interface with increased recording quality and stimulation. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) measurements demonstrated that polymerization of PEDOT at 1 V, compared to the common 2 V application, enhanced charge storage capacity and resulted in an impedance drop across all waveform types over a 1 Hz to 1 MHz frequency range[1,3]. Similar results also suggest that a DC waveform may be preferred over a sinusoid or square wave. Voltage excursion measurements taken across each waveform support this claim, indicating improved charge injection limits. These findings serve to accompany future in situ and in vivo PEDOT polymerization techniques to achieve optimal electrochemical properties for recording and stimulation purposes.
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