Pd/PMMA nanocomposite coated optical fiber hydrogen sensor operating at room temperature with humidity tolerance

A fiber optic hydrogen sensor coated with a palladium/polymethyl methacrylate (Pd/PMMA) nanocomposite layer is fabricated and benchmarked here. The sensor with Pd/PMMA substituted cladding, operates by intensity modulation technique through partial reflection in the sensing region. In-situ thermal reduction method has been adopted for nanocomposite synthesis due to reduced processing steps required and to avoid material waste. Benefitted from the hydrogen selective response of Pd nanoparticles and filtering ability of PMMA matrix, the sensor exhibits excellent resistance to humidity and good environmental stability in presence of interfering gases. Furthermore, it can detect low hydrogen concentration of down-to 0.1%, shows suppressed hysteresis and has response time of 25 sec to 4% hydrogen. All these features, combined with the feasible and cost-effective sensor preparation protocol, make the sensor a competitive candidate for hydrogen gas monitoring applications that operate at near room temperatures.