substituted by the groups x 1 x 2 and x 3 thus there can be different monomers in the polymers i e one or more of the functional groups in some of the monomer units are substituted with quaternary groups and some are unsubstituted i e x 1 x 2 and x 3 h in case t is nh i e chitin and chitosan x 1 x 2 and x 3 can also be these different monomers can be evenly distributed within the polymer structure or they can also form block structures the degree of substitution of the quaternary substituent in the polymer structure can be from 0 to 1 independently for each one of the groups x 1 x 2 and x 3 however the overall degree of substitution for all the groups x 1 x 2 and x 3 together being at least 0 01 in order to provide for a content of the necessary quaternary substituent in the polymer the maximum degree of substitution is 3 in which case there are three quaternary substituents per monomer in each monomer unit of the polymer a degree of substitution of for example 0 01 for a substituent means that there is on an average 1 of said substituents per 100 monomer units in the polymer and a degree of substitution of 1 means that there is on an average one substituent in each monomer unit in the polymer typically.