Enhancing the stability of all-solid-state astringent taste sensor through annealed solid contact and slow-drying lipid/polymeric membrane

The stability of the all-solid-state electrode (ASSE) is influenced by its fabrication procedure, which has been insufficiently investigated. In this study, we report that by applying direct annealing of solid contact (polypyrrole-carbon black [PPy-CB]), and slow-drying the membrane during fabrication, electrode capacitance is improved which determines the stability of the ASSE-based astringent taste sensor. The deposition of the PPy-CB by direct annealing accelerated the sensor fabrication time and improved the capacitance. The slow-drying method led to a thinner and denser membrane, which consequently reduced bulk and charge-transfer resistance and improved the electrode capacitance. In synergy with the annealed PPy-CB, the proposed sensor exhibited an areal capacitance of 9090 μF/cm2. In addition, the sensor maintained its linear response to the standard astringent substance (tannic acid), selectivity against various interfering taste substances, and retained repeatable measurements for at least 27 d.