Due to the properties arising from the synergism between the polyolefins and composites bearing polar functionalities, the unique behavior of these materials in bulk and in solution has led to emerging research in this area. Broad scientific effort, both fundamental and applied, has been devoted to obtain well-defined statistical, block and graft copolymers by covalently bonding polyolefins to amphiphilic polymers. It is well known that sequence distributions are major contributors in the adjustment of material properties in copolymers.
In this context, Markova et al. intended to use the synthetic advantages of acyclic diene metathesis (ADMET) polymerization (which offers a synthetic route to strictly linear polyethylenes functionalized at precise intervals) for the formation of new membrane materials for low temperature fuel cells. Well-defined, precise poly(vinylbenzyl phosphonic acid) (PVBPA)-containing-polyolefins were obtained for the first time by a combination of ADMET and atom transfer radical polymerization (ATRP), yielding a set of well-defined graft copolymers composed of polyethylene (PE) “backbone” and PDEVBP brushes, precisely placed on every 21st carbon. Quantitative deprotection of the phosphonates led to the corresponding polymer bonded phosphonic acids. The PA-containing electrolytes exhibited sufficient thermal properties with a high mobility for proton conduction. Moreover, the enhancement of the proton conductivity properties compared to the existing phosphonic acid containing block copolymer structures, the improved properties in the high temperature operating regime and the conductivity range make them interesting membrane materials for future studies.
Synthesis of proton conducting phosphonic acidfunctionalized polyolefins by the combination of ATRP and ADMET by Dilyana Markova, Kathleen L. Opper, Manfred Wagner, Markus Klapper, Kenneth B. Wagener and Klaus Mullen, Polym. Chem., 2013, 4, 1351-1363.
Julien Nicolas is a guest web-writer for Polymer Chemistry. He currently works at Univ. Paris-Sud (FR) as a CNRS researcher.
