The role of diazonium interface chemistry in the design of high performance polypyrrole-coated flexible ITO sensing electrodes

• DOI: 10.1016/j.elecom.2017.02.002
• Publication Date: 2017-02-05T20:47:01Z
• Authors: Momath Lo; Abdou K.D. Diaw; Diariatou Gningue...; Jean-Jacques Aaron; Mehmet A. Oturan; Mohamed M. Chehimi
• Keywords: Polypyrrole; Sulfonic acid

Abstract Benzene sulfonic acid-doped polypyrrole (PPyBSA) films were electrochemically prepared on aminobenzenediazonium-modified flexible ITO in aqueous media in a simple and efficient way. Diazonium electroreduction resulted in aminophenyl-modified ITO (ITO-NH2), which served as a platform for the electrodeposition of a PPyBSA layer. Without diazonium pretreatment, the PPyBSA coating delaminates readily upon sonication or during ultrahigh vacuum outgassing prior to XPS analysis. In contrast, a pretreatment involving electrografting for 45 s at − 800 mV resulted in excellent adhesion of PPyBSA, which withstood 75 min of ultrasonication. The robust ITO-NH2-PPy electrode was employed for the fast, simple and accurate detection of lead (II) by differential pulse voltammetry. The potentiometric response was linear in the Pb(II) concentration range 10− 8 to 2.5 × 10− 7 mol·L− 1 and the detection limit was 9.94 × 10− 10 mol·L− 1 at S/N = 3. This work demonstrates the central role of diazonium chemistry in producing an adhesive aryl monolayer on low-cost, flexible ITO electrodes, allowing the fabrication of robust, high-performance electrochemical-sensing conductive-polymer films.