Ammonia Sensing Properties Of Electrospun Lysine Based Materials-doped PANI/PAN Nanofiber Films

Conducting polyaniline(PANI), as one of the intrinsic conducting polymer, has been widely used in ammonia gas sensors. Because the response of pure PANI to ammonia is not very good, the response and recovery time are quite long, some researchers improved the ammonia sensitivity of PANI thin film through doping with certain materials. Based on lysine molecule which have two amino groups, lysine based materials are synthesized. The nitrogen of the amino groups are easy to form coordination bonds with proton, therefore, the ammonia sensitivity of PANI thin film doped with lysine based materials which are rich in amino groups would be influenced certainly.In this paper, L-lysine based materials which are rich in amino groups were synthesized. The polyaniline/polyacrylonitrile(PANI/PAN) thin film and PANI/PAN nanocomposite(NC) thin films doped with L-lysine based materials were obtained by electrospinning and in situ polymerization of aniline. The gas sensing properties of PANI/PAN thin film and PANI/PAN NC thin films doped with L-lysine based materials towards NH3, ethanol, acetone, chloroform and DMF were examined at room temperature.The experimental results reveal that PANI/PAN/ L-lysine based nanogel(4-Lys-4 nanogel)NC thin film exhibited a highly selective response toward NH3 at room temperature withimproved response kinetics. The PANI/PAN/4-Lys-4 nanogel NC thin film showed the response of 5.5 with response and recovery times of 22 s and 15 s, respectively toward100 ppm NH3, its detection limit could be 2.2 ppm. While the response of pure PANI/PAN thin film to 100 ppm ammonia is just 1.62. This response and recovery are quite fast compared with the reported works based on PANI doped with other materials.The enhanced response could be attributed to the large surface area, core-shell structure of the nanofibers and improved charge transfer as a result of a certain amount of amino groups doping PANI. Our results clearly indicate that PANI/PAN/4-Lys-4 nanogel NC thin film could effectively be used for the practical room temperature NH3 sensing application with quite fast response and recovery properties. At the same time, a new application of 4-Lys-4 nanogel on sensors is supplied.