There is no noticeable loss of membrane
conductivity for temperature values as high as 170 or 180 C,
as shown in Fig. 9. All of the membrane samples fall within a
conductivity range of 0.09e0.095 S cm1. This indicates that
the use of high hot-pressing temperatures causes no chemical
degradation of the Nafion 115 membrane. Actually, in the rollpress
method, membranes are exposed to high temperature
for a very short duration during the decal transferring step,
which excludes any substantial damage to the membrane.
The absence of any irreversible conductivity loss indicates
that the membrane experiences no de-sulfonation even when
exposed to high temperatures for a short duration. These results
confirm the successful application of the roll-press decal