Mechanistic Approach for Long-Term Stability of a Polyethylene Glycol–Carbon Black Nanocomposite Sensor

Abstract

Polymer−carbon nanocomposite sensor is a promising molecular sensing device for electronic nose (e-nose) due to its printability, variety of polymer materials, and low operation temperature; however, the lack of stability in an air environment has been an inevitable issue. Here, we demonstrate a design concept for realizing long-term stability in a polyethylene glycol (PEG)−carbon black (CB) nanocomposite sensor by understanding the underlying phenomena that cause sensor degradation. Comparison of the sensing properties and infrared spectroscopy on the same device revealed that the oxidation-induced consumption of PEG is a crucial factor for the sensor degradation. According to the mechanism, we introduced an antioxidizing agent (i.e., ascorbic acid) into the PEG−CB nanocomposite sensor to suppress the PEG oxidation and successfully demonstrated the long-term stability of sensing properties under an air environment for 30 days, which had been difficult in conventional polymer−carbon nanocomposite sensors.

Breath odor-based individual authentication by an artificial olfactory sensor system and machine learning

“…This suggests that the false identification in our study might be caused by the fluctuation/ instability of sensor responses and the performance of individual authentication would be better by improving the robustness of the sensing system/material. 22 In conclusion, we have demonstrated a primary study of breath odor sensing-based individual authentication using an artificial olfactory sensor system. The breath odor samples were tested by a 16-channel chemiresistive sensor array and the acquired sensor responses were analyzed by machine learning with a neural network algorithm.…”

“…This suggests that the false identification in our study might be caused by the fluctuation/instability of sensor responses and the performance of individual authentication would be better by improving the robustness of the sensing system/material. 22…”

Poly3‐Hexylthiophene Titanium Dioxide (P3HT‐TiO2) Composite Sensor for High Response Detection of Ammonia at Room Temperature

“…To assess the long‐term stability of the gas sensor, we conducted a 15‐day experiment to test the P3HT‐TiO 2 composite film sensor's response to NH 3 concentrations ranging from 1 ppm to 50 ppm, and the results of this investigation are presented in Figure 5(c). As depicted in the figure, the sensor's response gradually diminishes over time as the aging of the membrane and the disappearance of unstable adsorption sites come into play [51] . Nevertheless, the overall response of the sensor to NH 3 , even after the 15‐day testing period, remains within a satisfactory range, indicative of the commendable long‐term stability of the developed P3HT‐TiO 2 composite sensor.…”

“…As depicted in the figure, the sensor's response gradually diminishes over time as the aging of the membrane and the disappearance of unstable adsorption sites come into play. [51] Nevertheless, the overall response of the sensor to NH 3 , even after the 15-day testing period, remains within a satisfactory range, indicative of the commendable long-term stability of the developed P3HT-TiO 2 composite sensor. In order to investigate the gas selectivity of the composite film sensor, four different kinds of interfering gases were selected.…”