[17p-E102-1~20] 12.7 Biomedical Engineering and Biochips

▲ [17p-E102-9] Investigation of quinone dianion charge-transfer complex formation in PEDOT:lignosulfonate thin-films operating at physiological pH

〇(P)Alex ChiWei Tseng¹, Tomasz Rebis², Toshiya Sakata¹ (1.Univ. of Tokyo, 2.Poznan Univ. of Tech)

Keywords:conductive polymer, lignin, quinone

Conductive polymer films incorporating lignosulfonates (LS) are appealing for sustainable development of electrochemical devices such as biosensors. This is due to the natural abundance and low-cost of LS, which contains desirable functional groups such as quinones and sulfonic acids. In this study, we investigate the pH-dependent interaction between mobile carriers in PEDOT (poly(3,4-ethylenedioxythiophene) and quinone groups as both are electrochemically cycled in buffer solutions. Simultaneous voltammetry and charge transport characterization suggests the formation of a charge-transfer complex with reduced quinone dianions strongly bound to holes in oxidized PEDOT. This effect increases at higher pH ranges (pH > ~3) as the scarcity of hydrogen ions drives reduction of quinone away from hydroquinone. The resulting complex is effectively immobilized and shielded from further cycling, which has implications for the application of PEDOT:LS in physiological conditions.