Polymer-Based Conductometric Sensor for Acidic and Alkaline Vapors for Firefighting and CBRN Disaster Control

Mobile sensors are highly sought-after for multiple applications. For example, in firefighting or CBRN disaster control the presence of acidic and alkaline gases, such as hydrogen chloride and ammonia, poses a significant threat to personnel, demanding fast responding mobile sensors. However, current gas sensors are often costly and react specifically to individual analytes, making them unsuitable for non-specialized first response units. This study presents a novel approach using a cost-effective and user-friendly gas sensor with direct electrical readout. It is based on a hygroscopic polyethylene glycol (PEG) layer on miniaturized interdigitated electrodes. The adsorbed water in the polymer rapidly undergoes pH changes upon exposure to pH-changing vapors, leading to a drastic change in conductivity of the PEG. The experimental results demonstrate the sensor's ability to detect relevant concentrations of pH-altering gases, with a response time comparable to commercial sensors.