4: POLY(PHENYLENE ETHER)S 119
temperature dependence of the proton conductivity
suggests that the mechanism of charge transport is not
achieved by vehicular transport, but rather by a con-
certed series of hydrogen bond formation and break-
ing, which is termed a Grotthus mechanism. Obvi-
ously, from this behavior, a high proton conductivity
originates.
Mechanical stretching of sulfonated PPE shows a
great effect on electric properties [98]. Under favorite
conditions, electrical conductivities increase up to 10
times that of the original membranes.
Composite membranes prepared by casting
Nafion® 15 on films made from PPE and phospho-
molybdic acid show a lower methanol permeability in
comparison to pure Nafion® 15 [99]. The composite
membranes have a potential ...