Ultrasound Assisted Miniemulsion Polymerization for Preparation of Polypyrrole–Zinc Oxide (PPy/ZnO) Functional Latex for Liquefied Petroleum Gas Sensing

Abstract

Polypyrrole–zinc oxide (PPy/ZnO) hybrid nanocomposites have been synthesized using an ultrasound assisted in situ miniemulsion polymerization of pyrrole in the presence of ZnO nanoparticles. This synthesis approach results in the formation of hybrid functional colloidal particles with uniform size of around 100 nm, which can be used as a sensor for the detection of liquefied petroleum gas (LPG). FTIR analysis shows that the ZnO nanoparticles were encapsulated by the polymerized polypyrrole. Results obtained from TEM and X-ray diffraction analysis indicate that the PPy/ZnO composite particles give evidence of the crystalline nature of ZnO (Wurtize) and a well-defined hybrid nanocomposite structure, which is suitable for LPG sensor development. The controlled size of the hybrid particles obtained using this innovative synthesis strategy minimizes the response time to sense the LPG significantly (2.2 min for PPy/ZnO). The LPG sensing mechanism for the PPy(p-type)/ZnO(n-type) heterojunction has been presented through a change in the height of the barrier potential.