Highly sensitive ammonia sensor based on a PMMA/PANI microwire structure

In this paper, a highly sensitive ammonia (NH3) sensor based on a polymethyl methacrylate/polyaniline (PMMA/PANI) microwire structure is designed and implemented. First, a micron-sized PMMA microwire was fabricated and connected with two tapered single -mode fibers to form a coupling structure; thus, the Mach-Zehnder (MZ) interference was successfully excited due to the good light conductivity of the PMMA. It was demonstrated that the coupling structure behaved with a high refractive index detection sensitivity of 3044 nm/RIU. To make it sensitive to NH3, the PANI was selected to mix with PMMA and then formed a micron-level PMMA/PANI fiber. The experimental results showed that the PMMA/PANI fiber can selectively sense NH3 with a high sensitivity of 65.3 pm/ppm. This proposed NH3 sensor not only solves the problem of sensitive film shedding, but also possesses the advantages of good integration, high sensitivity, good selectivity, and short response time. (c) 2024 Optica Publishing Group