Ultra-sensitive optimized one-dimensional phononic crystal as a fluidic sensor to enhance the measurement of acetic acid concentration.

The current investigation theoretically presents a one-dimensional phononic crystal (PnC) as a fluidic sensor. The sensor under consideration aims to distinguish the concentration of acetic acid. The primary configuration of the proposed sensor is constructed with lead, epoxy, and a defect layer in the middle of the structure, that is filled with acetic acid (vinegar). As a result of the rise in density and decline in the speed of sound at a 100% concentration of acetic acid in comparison to pure water, the peak frequency of the output has shifted towards lower frequencies. Given that the maximum permissible concentration of acetic acid in water for vinegar is above 30%, sensor simulations were conducted within the concentration range of 25-35% with a step size of 1%. Interestingly, the sensitivity of the sensor exhibits a polynomial change in response to the concentration of acetic acid. Consequently, the highest level of sensitivity, which corresponds to the lowest concentration of vinegar, is recorded as 48.44 × 10 ⁶ (Hz). The proposed system exhibits a remarkable value of the quality factor of 2802.91. Furthermore, the optimal figure of merit (FOM) is achieved when the concentration is at its lowest, with a value of 94.00. Furthermore, the temperature effects are taken into account for a wide range between 10 and 60 °C. A pronouncing sensitivity is obtained for all temperatures changes and the highest one reached the value of 1.57 × 10 ⁶ (Hz/°C) at a temperature of 25 °C. Considering the present circumstances, the suggested sensor configuration has the potential to cater to a diverse array of other fluids, specifically their concentration and temperature, thereby offering a broad scope of applications.
(© 2024. The Author(s).)