BiPy obtained from Fluka (purity >99%, mp = 109-112[degrees]C) was used as received.
BiPy and MCI, in stoichiometric amounts relative to the functional ([greater than or equal to]N and - [CH.
The chloromethyl side-functionalized polysiloxanes (CMCI1-CMC13), and BiPy, in stoichiometric ratio related to the functional groups, were dissolved together in a [CHCl.
Side chloromethyl-functionalized polysiloxanes were reacted with BiPy (Menshutkin reaction) to obtain networks consisting of siloxane hydrophobic backbones interconnected between them through hydrophilic bridges with oppositely charged ion pairs (11), (12).
BiPy acts as a nucleophile agent forming bipyridinium salt with chloromethyl groups side attached to polysiloxane chains.
In fact, in the final network, the crosslinks by bipyridinium bridges can coexist with dangling BiPy units bound at one of the nitrogens only, and unreacted chloromethyl groups.