The present invention pertains to salt modified copolymers wherein one of the monomer units contains a quaternized N-atom structure with a polar substituent. The invention further relates to the use of said copolymers as dispersant especially for color filters. The copolymer is made by controlled polymerization or by conventional polymerization and comprises at least one monomer (MAr) selected from unsaturated monomers out of the group of acrylates, methacrylates, acrylamides, methacrylamides, styrenic monomers, at least one monomer (MBs) selected from unsaturated monomers out of the group of acrylates, methacrylates, acrylamides, methacrylamides, styrenic monomers wherein the monomer MB has a quaternized N-atom structure with a polar substituent selected from polyether, polyamine, nitrile, amide, imine, imide, ester, ketone, nitrile, aldehyde, diketone, ketoester, ketoamide, carbonate, carbamate, carbamide, sulfoxide, sulfone, carboxylic acid, sulfonic acid, phosphoric acid groups; or carboxylic acid anion, sulfonic acid anion or phosphoric acid anion groups which is formed as betaine structure r denotes the total number of monomers MA within the structural element (MAr) and r is >5, preferred 10-1000, most preferred 10-500; s denotes the total number of monomers MB within the structural element (MBs) and s is >1, preferred 2-100, most preferred 2-50.