Vol.:(0123456789) 1 3 J Mater Sci: Mater Electron DOI 10.1007/s10854-017-7519-9 Synthesis, characterization, material properties and sensor application study of polyaniline/niobium doped titanium dioxide nanocomposites M. T. Ramesan 1  · T. Sampreeth 1   Received: 20 May 2017 / Accepted: 11 July 2017 © Springer Science+Business Media, LLC 2017 1 Introduction During the last few decades, conducting polymers have opened up a promising ield in material science and engi- neering because of conducting polymer nanocomposites with metal oxide nanoparticles have enormous potential applications in sensors, energy storage devices, electro- chromic devices, membrane gas separation and so on [1–4]. Recently several studies have been carried out in progress with the fabrication and characterization of hybrid con- ducting polymeric material with inorganic nanoparticles as iller to enhance the mechanical behavior of conducting polymers. Among the conducting polymers, polyaniline (PANI) has been received a great attention due to its ease of synthesis, electrical and optical properties, low cost, unique doping/de-doping behavior and good stability [5–7]. It has been studied for a wide range of active materials like novel biosensors, energy storage devices and electrical devices [8–11]. The oxidation and protonation determines PANI’S electrical conductivity. However the only conducting form of PANI is its emeraldine base (EB) and it can be highly conductive when protonated. The conductivity of PANI is high as 10 2  S/cm [12]. Recently PANI with various inorganic nanomaterials has been investigated extensively because their properties are quite diferent from the isolated polymer chain [13]. However the applicability of conducting polymer remains limited because of its lack of processability and poor mechanical strength. The irregular structure of conducting polymers makes quite diicult in the investigation of con- ducting polymer. Nevertheless, to improve the structure and property the only possible way is to prepare polymer blend or composite materials with amazing properties [14–18]. Also the conducting polymer nanocomposites having metal oxide nanoparticles with organized structures has received Abstract Conducting polyaniline (PANI)/niobium doped titanium dioxide (Nb–TiO 2 ) nanocomposites with diferent weight percentages of Nb–TiO 2 nanoparticles were synthe- sized by an in situ polymerization method. The synthesized materials were characterized by FT-IR, UV, XRD, SEM, HRTEM, TGA, DSC and electrical conductivity measure- ments. Also, the ammonia gas sensing properties of PANI and its nanocomposites have been explored thoroughly. The FT-IR and UV spectra showed the clear evidences for the presence of nanoparticles by shifting to a broad peak, which indicates the interaction of nanoparticles with PANI. The XRD study reveals the crystalline nature of the fabri- cated nanocomposite. SEM and TEM analysis indicates the uniform dispersion of nanoparticles in the polymer matrix with spherically shaped particles having the nano- size region. TGA analysis showed the increased thermal stability of nanocomposites with an increase in concentra- tion of nanoparticles. The increase in glass transition and melting temperature with the increase in content of nano- particles were obtained from DSC. Both AC and DC con- ductivity and dielectric properties of the nanocomposites were increased with the increase in content of nanoparticles and the maximum electrical properties were obtained for 10 wt% of composite. The fabricated composites showed excellent sensitivity and fast response to ammonia gas at room temperature. The efect of nanoparticles in the pol- ymer chain increases the potential application of the con- ducting polyaniline, can act as multifunctional promising new material such as nanoelectronic devices and sensors. * M. T. Ramesan mtramesan@uoc.ac.in 1 Department of Chemistry, University of Calicut, Calicut, Kerala 673 635, India