bstituted phenyl group, which can be attached to the nitrogen by means of an alkylene group usually having from 1 to 3 carbon atoms, suitably 1 to 2 carbon atoms, and preferably Q is a benzyl group (???CH2???C6H5); and X??? is an anionic counterion, usually a halide like chloride. [0036] Examples of suitable monomers represented by the general formula (II) include quaternary monomers obtained by t