טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentCooper Hadas
SubjectDevelopment, Characterization and Simulation of Conductive
Polyaniline/Polymer Blends for Sensing of
Chemicals
DepartmentDepartment of Chemical Engineering
Supervisors Professor Emeritus Moshe Narkis
Professor Simcha Srebnik


Abstract

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.