title: Rapid Voltammetric Measurements at Conducting Polymer Microelectrodes Using Ultralow-Capacitance Poly(3,4-ethylenedioxythiophene):Tosylate.
abstract: We use a vapor-phase synthesis to generate conducting polymer films with low apparent capacitance and high conductance enabling rapid electrochemical measurements. Specifically, oxidative chemical vapor deposition was used to create thin films of poly(3,4-ethylenedioxythiophene):tosylate (
  
  
  
  tosylate). These films had a conductance of 17.1 ± 1.7 S/cm. Furthermore, they had an apparent capacitance of 197 ± 14 μF/cm(2), which is an order of magnitude lower than current commercially available and previously reported PEDOT. Using a multistage photolithography process, these films were patterned into
  
  
  
  tosylate microelectrodes and were used to perform fast-scan cyclic voltammetry (FSCV) measurements. Using a scan rate of 100 V/s, we measured ferrocene carboxylic acid and dopamine by FSCV. In contrast to carbon-fiber microelectrodes, the reduction peak showed higher sensitivity when compared to the oxidation peak. The adsorption characteristics of dopamine at the polymer electrode were fit to a Langmuir isotherm. The low apparent capacitance and the microlithographic processes for electrode design make
  
  
  
  tosylate an attractive material for future applications as an implantable biosensor for FSCV measurements. Additionally, the integration of
  
  
  
  tosylate electrodes on plastic substrates enables new electrochemical measurements at this polymer using FSCV.
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona , 1306 East University Boulevard, Tucson, Arizona 85721, United States.
authors.forename: Adam R
authors.initials: AR
authors.lastname: Meier
authors.affiliation: Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech , Building 345B, DK-2800 Kongens Lyngby, Denmark.
authors.forename: Marco
authors.initials: M
authors.lastname: Matteucci
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona , 1306 East University Boulevard, Tucson, Arizona 85721, United States.
authors.forename: Richard F
authors.initials: RF
authors.lastname: Vreeland
authors.affiliation: Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech , Building 345B, DK-2800 Kongens Lyngby, Denmark.
authors.forename: Rafael
authors.initials: R
authors.lastname: Taboryski
authors.affiliation: Department of Chemistry and Biochemistry, University of Arizona , 1306 East University Boulevard, Tucson, Arizona 85721, United States.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Heien