A Morphological Study of PFCB-Ionomer/ PVdF Copolymer Blend Membranes For Fuel Cell Application

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dc.contributor.authorMay, Nathanael Hendersonen
dc.contributor.committeechairMoore, Robert Bowen IIIen
dc.contributor.committeememberDillard, David A.en
dc.contributor.committeememberHendricks, Robert W.en
dc.contributor.committeememberWhittington, Abby R.en
dc.contributor.departmentMaterials Science and Engineeringen
dc.date.accessioned2017-04-04T19:49:44Zen
dc.date.adate2011-09-22en
dc.date.available2017-04-04T19:49:44Zen
dc.date.issued2011-08-11en
dc.date.rdate2016-10-07en
dc.date.sdate2011-08-22en
dc.description.abstractA new material for use as a proton exchange membrane in fuel cells has been developed: a blend of a perfluorocyclobutane-based block ionomer (S-PFCB) and Poly (vinylidene-co-hexafluoropropylene) (Kynar Flex, KF). This thesis details the work done thus far to characterize the morphology of this material, using small angle x-ray scattering, differential scanning calorimetry, atomic force micrscopy, and some other techniques to a lesser extent. Small angle x-ray scattering (SAXS) of pure S-PFCB showed a strong block copolymer- associated phase separation, on the order of 25 nm. Differential scanning Calorimetry (DSC) confirmed this finding. SAXS also revealed the presence of a peak representing individual ionic aggregates on the order of 3 nm. Finally, it was shown with DSC that no crystallinity develops in the S-PFCB block copolymer, while one of the blocks, known as 6F, crystallizes extensively. SAXS of incremental blend compositions of KF and S-PFCB revealed a steady increase in size of the block copolymer phase separation peak in SAXS, demonstrative of the miscibility of KF and the non-sulfonated 6F block of S-PFCB. Furthermore, this incremental study determined the scattering vector range relevant for comparing amounts of KF crystallinity. DSC of incremental blend compositions revealed two phases of KF crystallinity develops upon cooling a membrane, independent of cooling rate. Atomic force microscopy (AFM), small angle x-ray scattering (SAXS), and differential scanning calorimetry (DSC) corroborate to suggest a nonuniform morphology through the thickness of solution cast membranes. Also, the effect of different casting temperatures and after-casting anneals on morphology was assessed. Future work on this project involves morphological studies at various relative humidities and temperatures, as well as following up on discoveries already made. Finally, transmission electron micrscopy (TEM) should be performed to provide a visual analog, which will greatly help in developing an accurate morphological model.en
dc.description.degreeMaster of Scienceen
dc.identifier.otheretd-08222011-132132en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-08222011-132132/en
dc.identifier.urihttp://hdl.handle.net/10919/76853en
dc.language.isoen_USen
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectSolution Castingen
dc.subjectMorphologyen
dc.subjectSulfonated Aromatic Hydrocarbonen
dc.subjectPartially Fluorinated Ionomeren
dc.subjectProton Exchange Membraneen
dc.subjectPerfluorocyclobutaneen
dc.subjectKey terms: Small Angle X-ray Scatteringen
dc.titleA Morphological Study of PFCB-Ionomer/ PVdF Copolymer Blend Membranes For Fuel Cell Applicationen
dc.typeThesisen
dc.type.dcmitypeTexten
thesis.degree.disciplineMaterials Science and Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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