Ph.D Thesis

Ph.D StudentCohen Noa
SubjectSulfonated Polymer Systems Synthesized Using Emulsion
DepartmentDepartment of Materials Science and Engineering
Supervisor PROF. Michael Silverstein
Full Thesis textFull thesis text - English Version


High internal phase emulsions (HIPEs) are dispersions of one liquid within another with internal (dispersed) phase volume fractions over 74%. PolyHIPEs are highly porous crosslinked polymers that are typically synthesized within water-in-oil HIPEs by polymerizing a monomer and a crosslinking comonomer in the external (continuous) phase. The addition of monomers to both the external phase and the internal phase of high internal phase emulsions (HIPEs) can be used to synthesize bicontinuous polyHIPE systems containing two immiscible polymers. This type of synthesis could be used to produce a polymer system with conductive pathways through a non-conductive membrane. The objectives of this research were to synthesize bicontinuous elastomeric polyHIPEs containing sulfonated polystyrene conductive pathways, to characterize the resulting molecular structures, bicontinuous morphologies, and properties (physical, mechanical, thermal, and electrical), and to describe the relationships between the synthesis conditions (HIPE composition, HIPE stabilization, and sulfonation route) and the properties. The aqueous external phase of the oil-in-water HIPEs contained styrene sulfonate while the internal phase contained 2-ethylhexyl acrylate. The proton conductivity increased with increasing humidity and with increasing content of styrene sulfonate. PolyHIPEs based upon poly(styrene sulfonate) exhibited lower sulfur contents and lower ionic conductivities than a polyHIPE based upon sulfonated polystyrene.