Cation exchange behavior during the redox switching of poly (3,4-ethylenedioxythiophene) films

Abstract

Poly (3,4-ethylenedioxythiophene), PEDOT, films were synthesized at room temperature by potentiodynamic and potentiostatic step deposition in aqueous solutions containing EDOT monomer and LiClO4. In some solutions, the effect of small amounts of sodium dodecylsulfate, SDS, on the polymerization rate of EDOT and on the stiffness of the obtained PEDOT film was studied. The obtained PEDOT films were transferred in aqueous solutions containing cations with different molar mass, such as H+, Li+, Na+, K+, and Cs+. The apparent molar masses of the exchanged species during potentiodynamic experiments were determined by in situ microgravimetry. These measurements underlined the importance of the electrolyte chosen for electropolymerization process. It is known that SDS anions can be trapped inside the polymer layer during electropolymerization, providing them with a cation exchange behavior. However, even if the PEDOT films were deposited from an electrolyte without SDS, they still acted as cation exchangers.

Electropolymerized poly(3,4-ethylenedioxythiophene) coatings on porous carbon electrodes for electrochemical separation of metals

“…PSSis a polyanion and is sterically hindered once it is incorporated within the polymer blend, while a small ion like Clcan move more freely. [57] Since both anions are highly soluble in water we utilized aqueous polymerization.…”

Electropolymerized poly(3,4-ethylenedioxythiophene) coatings on porous carbon electrodes for electrochemical separation of metals

“…PSSis a polyanion and is sterically hindered once it is incorporated within the polymer blend while a small ion like Clcan move more freely. [47] Since both anions are highly soluble in water we utilized aqueous polymerization.…”

“…It has been reported that cations can be trapped in the polymer layer during the cycling of a similar PEDOT/sodium dodecylsulfate blend system. [47] Thus, the larger size of Ni 2+ (than Na + ) may have prevented its efficient removal during desorption. It is worth noting that the current plateau is reached early within the experiment time frame in chronoamperograms of electroadsorption and electrodesorption experiments (Figure S11a).…”

“…However, this ion exchange is not specific to anions, so cations and solvent molecules can be carried into the structure as well. [46,47] It is possible to tune this behavior by utilizing large dopant ions, such as polyanions, imparting permanent cation exchange property to the coating. Poly(4-styrenesulfonate) (PSS -) is a polyanion that is popularly blended with PEDOT via chemical or electrochemical means.…”

A comparative study of the effect of organic dopant ions on the electrochemical and chemical synthesis of the conducting polymers polyaniline, poly(o-toluidine) and poly(o-methoxyaniline)

“…Conducting polymers such as polyaniline and its derivatives (Qu et al 2020), polythiophene (Bazzaoui et al 1994), polypyrrole (Omastová and Mičušík 2012), and poly(3,4-ethylenedioxythiophene) (Gruia et al 2020) are used in a number of fields in industry such as corrosion protection of metals (Sazou and Deshpande 2017), conducting textiles (Tseghai et al 2020), biosensors and gas sensors (Yin et al 2006), electrocatalysis (Gustafson et al 2014), electrochromic display devices (Tian et al 2017), supercapacitors (Deshpande et al 2013), and in rechargeable batteries (Hong et al 2020). This is due to their excellent features such as low cost, environmental stability, light weight, and good electrical properties.…”