Preparation and analyses of directly sulfonated poly(vinyl fluoride),
PVF, membranes have been performed. Electron beam or proton irradiatio
n was used for the production of reactive sites. Ion-exchange capacity
, sulfonation efficiency and ion conductivity were analysed. Increases
in the absorbed dose and in the linear energy transfer were found to
have a promoting effect on the sulfonation rate and sulfonic acid cont
ent. In addition, compared with commercial ion-exchange materials, qui
te high ion-exchange capacities were achieved. The highest measured io
nic conductivity of the materials was 20 mS cm(-1), which was achieved
with proton-irradiated samples after long sulfonation times. On the b
asis of the results the proton irradiation is believed to cause the fo
rmation of channels with higher sulfonic acid content than those found
in other domains of the matrix. The presence of these channels increa
ses the ionic conductivity.