Understanding the sensing mechanism of polyaniline resistive sensors. Effect of humidity on sensing of organic volatiles

摘要: Abstract Polyaniline (PANI) is the oldest and potentially one of most useful conducting polymers. Among other technological applications, PANI films have been extensively used as resistive sensors volatile analytes. However, at present mechanism underlying resistivity changes upon exposure to substances still unclear. In this work, we investigate different effects absorption which can cause polymer electrical resistance when it acts sensor. This model takes into account three major components: (i) in electronic structure polymeric chains (ΔRele), (ii) variations electron hopping process (ΔRhop) (iii) ionic conductivity between due dielectric medium them (ΔRmed). Using two point probe resistivity, UV–visible spectroscopy, environmental ellipsometric porosimetry atomic force microscopy study effect volatiles on polyaniline properties improve understanding changes. Specifically, case water absorption, seem be associated with swelling (in high humidity range). It found that ambient not only gives a signal but also strongly affect sensing (e.g. ethanol).