Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)

Legacy Department



Smith, Jr., Dennis W.

Committee Member

Dieter, Karl R.

Committee Member

Tennyson, Andrew G.


Perfluorocyclobutyl (PFCB) aryl ether copolymers are excellent candidates for proton exchange membrane (PEM) component in PEM fuel cells. Sulfonated PFCB copolymer membranes exhibit not only high chemical/thermal/mechanical stability but also high proton conductivity. In this regard, PFCB aryl ether copolymers were synthesized via thermal step-growth [2 + 2] cyclopolymerization from aryl bis-(trifluorovinyl ether) (TFVE) monomers and oligomers. Experimental and computational studies confirmed that copolymerization of relatively electron-rich and electron-poor TFVE monomers gave selective-segmented copolymers in an one-pot polymerization. After sulfonation, the PFCB copolymers comprising hydrophilic and hydrophobic segments gave membranes with high proton conductivity. Cross-linked membranes of the sulfonated PFCB copolymers were also prepared via Friedel-Craft acylation to improve their mechanical properties and manage the high stress due to hydration/dehydration induced swelling. A phosphonic acid telechelic PFCB aryl ether ionomer was also synthesized and used as a grafting compound to inorganic fillers. The tailorable synthetic methodology, chemical/physical properties, effect of sulfonation level, block length and cross-linking of copolymers on water uptake, volume swelling, proton conductivity, and thermal properties and their potential application in PEM fuel cells is presented.