Poly (m-amino benzene sulfonic acid)-based composites on plastic substrates: A simple and cost effective approach towards low ppm ammonia detection at room temperature and kinetic analysis

Because of intimidating toxicity of ammonia, development of ultra-sensitive, as well as portable and energy efficient ammonia sensor is of paramount importance. Here, we report a simple as well as cost-effective synthesis protocol of graphite- poly-amino benzene sulfonic acid (Graphite -PABS) nanocomposite via an in-situ chemical oxidative polymerization pathway. The ammonia sensing characteristics of graphite - PABS composite based sensors on low cost plastic substrate has been investigated in the concentration range of 10-100 ppm of ammonia in air at room temperature. While the sensitivity for sensors comprising only PABS is about 136.38%, the graphite -PABS nanocomposites demonstrated an appreciably high value of about 282.5% towards 100 ppm of ammonia. The sensors have not only demonstrated high sensitivity, selectivity and fast recovery; they are operable at room temperature and hence consume considerably low power compared to the conventional metal-oxide sensors. Furthermore, we have fitted the response and recovery transients of conductance of graphite/ PABS based cost effective sensor using two sites Langmuir adsorption kinetics to explain the plausible ammonia sensing mechanism of graphite loaded PASS sensor. Low concentration ammonia sensing characteristics of this newly synthesized graphite/PABS composite on the plastic substrate is first demonstrated by our group