Disclosed are multi-purpose polymers that are the polymerization product of a monomer mixture comprising at least one amino-substituted vinyl monomer; at least one nonionic vinyl monomer; at least one associative vinyl monomer; at least one semihydrophobic vinyl surfactant monomer; and, optionally, comprising one or more hydroxy-substituted nonionic vinyl monomer, crosslinking monomer, chain transfer agent or polymeric stabilizer. These vinyl addition polymers have a combination of substituents, including amino substituents that provide cationic properties at low pH, hydrophobic substituents, hydrophobically modified polyoxyalkylene substituents, and hydrophilic polyoxyalkylene substituents. The polymers provide surprisingly beneficial rheological properties in acidic aqueous compositions, and are compatible with cationic materials. The multi-purpose polymers are useful in a variety of products for personal care, health care, household care, institutional and industrial care, and industrial applications.