Negatively charge monomer

There are a number of combinations for the choice of diamine and acid chloride monomers. For example, if trimesoyl chloride, which has three -COCl groups in an aromatic ring, is mixed with phthaloyl chloride, which has two -COCl groups, crosslinking will form between two main chains. Unreacted -COCl will become -COOH upon contact with water and the membrane will become negatively charged. Monomers with reactive groups other than amine and acid chloride can also be used. 

To describe the solubility of sodium poly(styrene sulfonate) in the presence of z-valent counterions, the electrostatic model [18,19] was introduced. This model takes into account a short-range electrostatic attraction between negatively charged monomers (1) and those carrying condensed multivalent counterions that are positively charged (z 1). Phase diagrams have been calculated using two techniques the polymer reference interaction site model (PRISM) [18] and the random phase approximation (RPA) [19]. Both techniques lead to the spinodal equation... 

The negatively charged monomers ol polyelectrolyte chain are shown in blue and neutral monomers in gray. Positively charged counterions are shown in pink. 

Note that the dependence of the number of monomers in a bead on the fraction of positively and negatively charged monomers and charge asymmetry (eqn [206]) has a similar functional form as a head size dependence on the fraction of the condensed counterions and charged monomers in the case of a polyelectrolyte chain when the chain collapse is caused by counterion condensation. ... 

Polyampholytes are charged polymers with both positively and negatively charged monomers. In this case the Coulombic interactions between charges are not only repulsive, as in the case of polyelectrolytes, but are also... 

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