In-Situ Synthesis of Poly (An-co-m-TFMA) Electro Active Copolymer: Characterization and Application as Humidity Sensor.

A new series of polyaniline based nanocomposites has been synthesized by using chemical oxidative polymerization of aniline (An) with m-trifluoromethyl aniline (TFMA) doped dodecylbenzene sulphonic acid (DBSA). The prepared copolymer composites were characterized by using different analytical techniques such as UV-visible, FT-IR, Scanning electron microscopy (SEM), X-ray diffraction methods (XRD) and humidity sensing techniques. The Conducting properties of these nanocomposites was studied by using standard four probe method. The particle size ranges from 100 nm to 200 nm diameters was observed in SEM analysis and surface morphology shows solid granular layers of nano pillared like structures. XRD pattern shows that the amorphous nature of the copolymer particles. Interestingly the electrical conductivity of this nanocomposite was found to be 1.807 x 10^-4 S/cm. The solubility tests of these composites show good solubility than that of polyaniline homopolymer. The humidity sensing mechanism was studied, based upon the resistance variations due to the absorption of water vapour. The poly (An-co-m-TFMA) thin film was prepared by spin-coating method and humidity sensing ability was compared. It was observed that by the change of relative humidity (%RH) from 10% to 70%. [ABSTRACT FROM AUTHOR]