H2S sensing using in situ photo-polymerized polyaniline-silver nanocomposite films on flexible substrates

We demonstrate the preparation of flexible polyaniline-silver (PANI-Ag) nanocomposite films via an in situ facile UV induced polymerization of aniline in presence of AgNO3. The flexible substrates used were (3-aminopropyl) trimethoxysilane (APTMS) modified biaxially oriented polyethylene terephthalate (BOPET) substrates. The APTMS modification of BOPET surface has two advantages: (i) improved adhesion of the films, and (ii) directional growth of polymer perpendicular to the substrate plane, leading to nanobrush-like morphology. The PANI-Ag films have been characterized by various techniques, such as, UV/Vis, FTIR, Raman, SEM and XPS. These films were found to be highly selective and sensitive to the H2S i. e. chemiresistive response of similar to 100% at 10 ppm with a reasonably fast response time of 6 min. PANI-Ag films prepared on pristine BOPET exhibits chemiresistive response of similar to 67% at 10 ppm of H2S exposure. In contrast pure PANI films did not exhibit any response on exposure to H2S. The plausible mechanism(s) of H2S sensing have been discussed. This study highlights the importance of surface modification and the role of Ag in PANI matrix for H2S sensing. (C) 2013 Elsevier B.V. All rights reserved.