Electropolymerization of Various Aromatic Monomers Using Streaming Potentials

Abstract

Bipolar electrodes, i.e., wireless electrodes driven by an external electric field, have been paying more and more attention1. Electrolysis using bipolar electrodes is an eco-friendly electrolysis system because they work with a low concentration of supporting electrolytes, which become waste after reactions. Indeed, we achieved the electrochemical fluorination on the bipolar electrodes, reducing the amount of supporting electrolyte to 1/100 compared to a conventional electrolysis2. However, in bipolar electrolysis, driving electrodes are necessary to generate an external electric field, which creates concern regarding the side reaction occurring on the driving electrode. Streaming potentials can be promising candidates to solve this problem. Streaming potentials are the potential differences between an inlet and an outlet of a narrow channel, which is generated when low-concentrated electrolytes are fed into the channel3. In the previous work, we developed a bipolar electrode system using the streaming potential4. The streaming potential was successfully generated by filling the cotton into a narrow channel to conduct the electropolymerization of pyrrole and 3,4-ethylenedioxythiophene. Yet, a large pressure drop of about 10 MPa is needed in this case. Moreover, the value of streaming potential is still low and the monomer scope was limited to pyrrole and 3,4-ethylenedioxythiophene.In this study, we aimed to investigate the condition with a low-pressure drop and a high-streaming potential, which enabled to expand the scope of electropolymerization. The screening of the filling declared that a polymer monolith, a porous material having continuous pores, was the best filling material for electrolysis. Then, the electropolymerization of thiophene and the ruthenium monomer, which could not be polymerized with the cotton-filled channel because of a low-streaming potential, was successfully carried out to obtain the corresponding polymers. The details of the streaming potential measurement and electropolymerization will be presented in the talk.References N. Shida, Y. Zhou, S. Inagi, Acc. Chem. Res., 2019,52, 2598–2608.K. Miyamoto, H. Nishiyama, I. Tomita, S. Inagi, ChemElectroChem, 2019, 6, 97–100.A. V. Delgado, F. González-Caballero, R. J. Hunter, L. K. Koopal, J. Lyklema, J. Colloid Interface. Sci., 2007, 309, 194–224.S. Iwai, T. Suzuki, H. Sakagami, K. Miyamoto, Z. Chen, M. Konishi, E. Villani, N. Shida, I. Tomita, S. Inagi, Commun. Chem., 2022, 5, 66. Figure 1