Electrochemical and Optical Properties of the Poly(3,4-ethylenedioxythiophene) Film Electropolymerized in an Aqueous Sodium Dodecyl Sulfate and Lithium Tetrafluoroborate Medium
- EDOT has a higher oxidation potential than water, which makes polymers electropolymerized from water "poorly defined".
- Addition of SDS lowers the oxidation potential to 0.76V, below that of EDOT in acetonitrile at 1.1V.
- " The potential was first switched from open circuit potential to 0.5 V for 100 s before polarizing the electrode to the desired potential. This initial step was to allow double-layer charging of the Au electrode|solution interface, which minimizes the distortion of the polymerization current transient by double-layer capacitance charging.17,18 "
- Plated at 0.82 - 0.84V, 0.03M EDOT conc.
- 0.1M LiBF4 anion / electrolyte; 0.07M SDS sufactant.
- This SDS is incorporated into the film, and affects redox reactions as shown in the cyclic voltammagram (fig 4)
- BF4-, in comparison, can be driven out of the film.
Improvement of the Electrosynthesis and Physicochemical Properties of Poly(3,4-ethylenedioxythiophene) Using a Sodium Dodecyl Sulfate Micellar Aqueous Medium
- "The oxidation potential of thiopene = 1.8V; water = 1.23V.
- Claim: "The polymer films prepared in micellar medium [SDS] are more stable than those obtained in organic solution as demonstrated by the fact that, when submitted to a great number of redox cycles (n ≈ 50), there is no significant loss of their electroactivity (<10%). These electrochemical properties are accompanied by color changes of the film which turns from blue-black to red-purple upon reduction."
- Estimate that there is about 21% DS- anions in the PEDOT - SDS films.
- I'm still not sure about incorporating soap into the electroplating solution.. !
Electrochemical Synthesis of Poly(3,4-ethylenedioxythiophene) on Steel Electrodes: Properties and Characterization
- 0.01M EDOT and 0.1M LiClO4 in acetonitrile.
- Claim excellent adhesion & film properties to 316 SS.
- Oxidation / electrodeposition at 1.20V; voltages higher than 1.7V resulted in flaky films.
PMID-20715789 Investigation of near ohmic behavior for poly(3,4-ethylenedioxythiophene): a model consistent with systematic variations in polymerization conditions.
- Again use acetonitrile.
- 1.3V vs Ag/AgCl electrode.
- Perchlorate and tetraflouroborate both seemed the best counterions (figure 4).
- Figure 5: Film was difficult to remove from surface.
- They did use a polycrystaline Au layer:
- "The plating process was allowed to run for 1 min (until approximately 100 mC had passed) at a constant potential of 0.3 V versus Ag/AgCl in 50 mM HAuCl4 prepared in 0.1 M NaCl."
- Claim that the counterions are trapped; not in agreement with the SDS study above.
- "Conditions for the consistent production of conducting polymer films employing potentiostatic deposition at 1.3 V for 60-90 s have been determined. The optimal concentration of the monomer is 0.0125 M, and that of the counterion is 0.05 M. "
PMID-24576579 '''Improving the performance of poly(3,4-ethylenedioxythiophene) for brain–machine interface applications"
- Show that TFB (BF4-) is a suitable counterion for EDOT electropolymerization.
- Comparison is between PEDOT:TFB deposited in an anhydrous acetronitrile solution, and PEDOT:PSS deposited in an aqueous solution.
- Presumably the PSS brings the EDOT into solution (??).
- figure 3 is compelling, but long-term, electrodes are not that much better than Au!
- Maybe we should just palate with that.
-
PEDOT-modified integrated microelectrodes for the detection of ascorbic acid, dopamine and uric acid
- Direct comparison of acetonitrile and water solvents for electropolymerization of EDOT.
- "PEDOT adhesion is best on gold surface due to the strong interactions between gold and sulphur atoms.
- images/1353_2.pdf
|