Polyaniline nanofiber composites with metal salts: Chemical sensors for hydrogen sulfide

A bulk synthetic method that yields uniform polyaniline nanofibers with narrow size distribution, which can be adjusted from 30 to 120 mm, was analyzed. The polyaniline nanofibers used as chemical sensors offers high surface area and small diameter, which facilitates the diffusion of molecules and dopants into the nanofibers. In this experiment, as a result new composite materials were formed from metal salts and polyaniline nanofibers, which show an enhanced response to hydrogen sulfide. The reaction between H₂S and metal occurs with metal ions coordinated to polyaniline whereas a metal salt is added to polyaniline the metal cation coordinates both the imine and amine nitrogen atoms on the polyaniline chains. The mechanism of H₂S with the metal salt to form the corresponding metal sulfide is offered. These new materials have great potential to control the response of conducting polymers to various chemicals along with other new applications.