A new evanescent wave ammonia sensor based on polyaniline composite

Area of Science:

• Photonics and optical sensing
• Materials science for chemical detection
• Integrated optics

Background:

• Ammonia gas detection is crucial for environmental monitoring and industrial safety.
• Conventional optical ammonia sensors often lack sufficient sensitivity and integration capabilities.
• Development of novel sensing materials and integrated optical platforms is needed.

Purpose of the Study:

• To design and develop a single-mode optical planar waveguide ammonia sensor.
• To investigate the sensing properties of a polyaniline/polymethyl methacrylate (PANI/PMMA) composite for ammonia detection at room temperature.
• To evaluate the influence of interaction length on the sensor's metrological parameters.

Main Methods:

• Fabrication of a single-mode TE(0)-TM(0) optical planar waveguide.
• Integration of a polyaniline/polymethyl methacrylate (PANI/PMMA) composite as the sensing layer.
• Characterization of the sensor's response to ammonia gas exposure at room temperature.
• Analysis of metrological parameters including sensitivity, response time, and recovery time as a function of interaction length.

Main Results:

• A significant change in guided light output power was observed upon exposure to ammonia.
• The sensor exhibited high sensitivity to ammonia at room temperature.
• Metrological parameters were found to be strongly dependent on the interaction length of the sensing region.
• The integrated optical sensor demonstrated superior sensitivity compared to conventional absorption spectroscopy methods.

Conclusions:

• The PANI/PMMA based optical planar waveguide sensor is a promising platform for sensitive ammonia detection.
• The integrated optical design offers advantages in sensitivity and potential for miniaturization.
• Optimizing interaction length is key to enhancing sensor performance for ammonia sensing applications.