Electrospun polypyrrole-polyethylene oxide coated optical fiber sensor probe for detection of volatile compounds

In this work, a multimode optical fiber sensor probe coated with polypyrrole-polyethylene oxide (PPO) nanofibrous mat is investigated to detect volatile compounds such as ammonia, triethylamine, methanol, ethanol and acetone vapours. The fibrous mat on the fiber cladding is deposited using electrospinning method followed by vapour phase polymerization. The affinity of PPO towards different volatile compounds changes the effective refractive index of optical fiber cladding, modulating the intensity of the transmitted spectrum. The intensity variation in presence of volatile vapours of different concentration is investigated to determine the responses of the sensor probe. The sensor probe shows different detection limit such as 0.1 ppm, 2 ppm, 2 ppm, and 1 ppm and recovery time of 10 min, 54.4s, 21.06 s and 11.08 s for ammonia, ethanol, methanol and triethylamine vapours respectively. Thus, the electrospinning technique can be used for coating optical fiber cladding with special material such as PPO to develop optical fiber based sensor to detect trace amount of volatile compound.