For example, the first polymer can include about 10 to about 20 or about 12 to about 20 weight percent of carboxylate salt monomer units.In one embodiment, the second polymer includes the cationic monomer unit represented by Chemical Structure II: or a quaternized adduct thereof, wherein R1, R3 and R4 are, independently, hydrogen or an alkyl group and R2 is an alkyl group.