Eletrodos impressos fabricados com uma tinta condutora de grafite e acetato de celulose: efeito do envelhecimento dos eletrodos nas propriedades eletroquímicas

Abstract

The screen-printing technique has been widely explored in the field of electroanalysis as it enables the reproducible, large-scale, and cost-effective fabrication of electrochemical sensors. Among the materials used for constructing these sensors, carbon-based conductive inks have attracted significant attention due to their excellent electrical, mechanical, and chemical properties. In this context, the objective of this study was to evaluate the performance of screenprinted carbon electrodes manufactured with a conductive ink prepared from graphite powder, cellulose acetate, and acetone. The cyclic voltammetry technique was employed to investigate the electrochemical properties of the electrodes, utilizing the ferrocyanide ion as a redox probe. The results revealed that the freshly prepared electrodes exhibited a satisfactory voltammetric profile for the redox probe. However, as the electrodes aged, a gradual alteration in the voltammetric profile was observed, indicating that electrode aging influences the electrochemical properties. To produce electrodes with more stable electrochemical properties, a drying step in an oven was introduced during the fabrication process, obtaining ΔEp = 103 ± 1 mV, RSD = 1 % and ipa = 32 ± 1 µA, RSD = 3 %, compared to the first batch built with results of 116 ± 18 mV, with RSD = 16 % and ipa = 27 ± 2 µA, RSD = 7%. Although this resulted in a slight improvement in the electrochemical properties, they still exhibited variations over time. Nevertheless, no significant variations were observed within a period of ten days, indicating this period is suitable for the reproducible utilization of the screen-printed electrodes. The screen-printed electrodes fabricated in this study demonstrated, qualitatively, a considerably larger electrochemically active area compared to commercial electrodes, and the reproducibility of device fabrication was similar to that of commercial electrodes. Thus, this work demonstrated the great potential of the developed carbon conductive ink, composed of graphite powder, cellulose acetate, and acetone, for the production of printed carbon electrodes using the screen-printing technique. The results we have obtained showed the importance of controlling electrode aging to maintain their electrochemical properties over time. The screenprinted electrodes fabricated in this study were promising devices due to their larger electrochemically active area, however, further studies are necessary to optimize the fabrication process and improve the long-term stability of the electrodes.