Flexible colorimetric sensor system for real-time gas detection with image-based analysis

Growing concerns over environmental stability have increased demand for colorimetric humidity sensors due to their rapid, battery-free detection capabilities. This study introduces a flexible, wearable sensor based on a color-coded resonant array (CCRA) and humidity-responsive polyvinyl alcohol (PVA). The sensor shifts resonance wavelengths via PVA swelling and contraction, achieving nearly 100% RGB gamut coverage with response times of 180 ms (swelling) and 210 ms (shrinking). Segmented zones enable systematic gas detection, and differential swelling responses allow detection of various volatile organic chemicals (VOCs). Adaptable for wearable and industrial use, this sensor offers reconfigurable and real-time atmospheric monitoring solutions.