Spectroscopic and electrical properties of polyaniline/CeO₂ composites and their application as humidity sensor

Abstract

Polyaniline/CeO 2 composites were synthesized by in situ chemical polymerization method using ammonium persulphate as an oxidizing agent. This is the single step polymerization process for the direct synthesis of emeraldine salt phase of polymer. The polymers were characterized by using FTIR spectral analysis, SEM, and XRD studies. Formation of conducting emeraldine salt phase is confirmed by spectroscopic techniques. High temperature conductivity measurements show ''thermal activated behavior.'' The change in resistance with respect to percentage relative humidity (% RH) is observed, when the pressed pellets of the polymer were exposed to the broad range of humidity (humidity ranging between 10 and 95% RH).

DC electrical conductivity and rate of ammonia vapour-sensing performance of synthetic polypyrrole–zirconium(IV) phosphate cation exchange nanocomposite

“…The magnitude of the conductivity is dependent on the number of charge carriers available and their mobility. It has been observed that mobility of charge carriers increases with the increase in temperature leading to the increase in conductivity similar to that reported for PANI/WO 3 and PANI/CeO 2 nanocomposites [22,23]. Another factor which also affects the electrical conductivity is the molecular alignment of the chains within the entire system.…”

“…1. Significant change in electrical conductivity of the nanocomposite was observed with the rise in temperature; electrical conductivity of PPyZrP increasing with increase in temperature can be explained by ''thermal activated behaviour'' [22]. The conduction mechanism in the conducting polymers is explained in terms of polaron and bipolaron formation.…”

Electrical and thermal studies on poly(3-methyl thiophene) and in situ polymerized poly(3-methyl thiophene)cerium(IV)phosphate cation exchange nanocomposite

“…Another factor which also affects the electrical conductivity is the molecular alignment of the chains within the entire system. Parvatikar et al [36,37] have explained the rise in electrical conductivity in their PANI/WO 3 and PANI/CeO 2 nanocomposites on the basis of thermal curing leading to a better alignment of the polymer chains, which increases the conjugation length, and hence an increase in electrical conductivity. Also, molecular rearrangement takes place during heating which makes the molecular conformation favorable for electron delocalization [38].…”

“…1. It was observed that the electrical conductivity of the nanocomposite increases with the rise in temperature, which is the characteristics of ''thermal activated behavior'' [36]. To explain the conduction mechanism in the conducting polymers, the concept of polaron and bipolaron was introduced.…”

Synthesis of Ba-doped CeO2nanowires and their application as humidity sensors

“…Recent investigations have presented that humidity sensors based on CeO 2 powder show poor sensitivity [9], but that a humidity sensor based on CeO 2 nanowires has shown a fast response [10].…”