Development of gas sensors coatings by polyaniline using pressurized fluid

The objective of this work was to develop gas sensors using three different techniques for the deposition of polyaniline film: (a) precipitation of polyaniline particles doped with dodecylbenzenesulfonic acid (DBSA) using supercritical carbon dioxide (SC-CO2), (b) rapid expansion with SC-CO2 (modified RESS) of polyaniline doped with DBSA, and (c) in situ polymerization polyaniline doped with chloridric acid. The sensors responses were evaluated at moisture and volatile organic compounds (VOCs). All of the sensors presented a satisfactory sensitivity and reversibility when exposed to VOCs. The films morphology was characterized by scanning electronic microscopy for field emission (FE-SEM). Results showed a difference regarding phase formation and behavior for the sensors obtained using SC-CO2 coatings with polyaniline and by in situ polymerization, indicating that techniques the use of supercritical fluid techniques are promising in manufacturing such electronic devices.