|M.Sc Student||Cooper Hadas|
|Subject||Development, Characterization and Simulation of Conductive|
Polyaniline/Polymer Blends for Sensing of
|Department||Department of Chemical Engineering||Supervisors||PROFESSOR EMERITUS Moshe Narkis|
|ASSOCIATE PROF. Simcha Srebnik|
Intrinsically conductive polymers (ICPs), such as polypyrrole (PPy) and polyaniline (PANI), have a number of interesting features that make them potentially important materials for various types of sensors. Development, characterization and performance understanding of sensing materials for liquids, based on melt-processed electrically conductive PANI/polymer blends, are the focus of this research project. In the present study, melt-processed electrically conductive blends, containing two immiscible polymers (ethylene vinyl acetate copolymer, EVA-19, and copolyamide 6/6.9, CoPA) and PANI, with and without a compatibilizer, have been investigated. The EVA-19/CoPA/PANI blends showed a preferred localization of PANI in the CoPA phase. This structure was also demonstrated using molecular simulations of the hydrogen-bonded polymers. Electrically conductive EVA-19/CoPA (70/30)/30phr PANI filaments, produced by a capillary rheometer process at various shear rate levels were studied as sensing materials for a homologous series of alcohols. All filaments displayed a sharp decreasing resistance upon exposure to these solvents, and the resistance changes upon repeating exposure/drying cycles have revealed (most filaments) a reversible and reproducible sensing behavior. An EVA grafted maleic anhydride (EVA-g-MA) compatibilizer was chosen to improve compatibility of EVA-19 with CoPA, hence modification of the blend containing PANI, and thus modification of the sensing properties. Electrically conductive EVA-19/CoPA (70/30)/30phr PANI/2phr EVA-g-MA filaments were formed more sensitive and exhibited an improved sensing behavior (at a high shear rate level), as compared to the corresponding uncompatibilized filaments. Filaments containing 5 phr EVA-g-MA were more sensitive, compared to the 2 phr EVA-g-MA filaments, but their resistance stability and reproducibility were of inferior quality compared with the 2 phr EVA-g-MA filaments.