The synthesis of this membrane was obtained
by sol-gel process with different steps. It was
based on the hydrolysis condensation of the
benzyl-triethoxylane precursor in a methanol solution
containing water and triflic acid (F3SO3H).
The steps of preparation are indicated elsewhere
[79] and their structure is as shown in Fig. 10.
The polymer was sulphonated in dichloromethane
solvent using chlorosulfonic acid. Several copolymer
compositions prepared from different
proportions of the mixture of benzyl-triethoxysilane,
n-hexyltrimethoxysilane and ethoxysilane
(e.g. different organically modified alkoxy
silanes). Crosslinking was also performed in THF
by hydrosilylation of silane groups with divinylbenzene
using divinyltetramethyldisiloxane platinum
complex as catalyst.