Environmental responses of polyaniline inverse opals: Application to gas sensing

Much attention has been directed toward the fabrication of nanostructured polyaniline and its applications. In this study, we examined the potential of polyaniline inverse opals as sensors. The inverse opals were chemically synthesized via templating polystyrene colloidal crystals and then subjected to four response tests: dry gas flow, ethanol vapor, hydrogen chloride, and ammonia. The three-dimensionally ordered macroporous polyaniline was of good quality as observed by scanning electron microscopy. The samples demonstrated high sensitivity and fast response to different conditions, which may be due to the porosity facilitating diffusion and large surface area interacting with substances. Moreover, the effect of the structural order on the responses is discussed.