Polydimethylacrylamides (PDMAs) end-functionalized with hydrophobic groups were synthesized by the reaction of cesium salts of one- or two-ended living PDMA anion with octadecanoyl and perfluorooctanoyl chlorides and with alpha -phenylacrylate monomers containing an octadecyl group attached via oligooxyethylene spacers to the acrylate functionality. Size exclusion chromatography or NMR studies indicated that the end functionalizations were nearly quantitative. Reduced viscosity measurements were consistent with predominantly dimeric association of the perfluorooctanoyl-end-functionalized PDMAs. The association of the two-ended, perfluorooctanoyl- and octadecanoyl-functionalized polymers was more extensive and consistent with pairwise association. Furthermore, the presence of oligoethylene oxide spacers between the octadecyl and alpha -phenylacrylate groups greatly enhanced the hydrophobic association of bis(octadecyl)-end-functionalized PDMA.