We prepared two copolymer precursors of N,N-dimethylacrylamide containing the reactive comonomer N-acryloxysuccinimide. One was obtained by conventional radical polymerization (Mn) 251 600 g‚mol -1 ; Mw/Mn) 2.20) and the other by controlled radical polymerization using the RAFT (reversible addition-fragmentation chain transfer) process (Mn) 49 200 g‚mol -1 ; Mw/Mn) 1.21). We used these precursors to prepare hydrophobically modified chains containing grafted dodecyl (DO) groups and fluorescent dyes: pyrene (PY), phenanthrene (PHE), or anthracene (AN). The interaction of these polymers with an anionic surfactant, sodium dodecyl sulfate (SDS), was studied by steady-state and time-resolved fluorescence. By following the formation of PY excimer and measuring the efficiency of energy transfer from PHE to AN labeled chains, we characterized the dynamics of association and the type and morphology of the resulting hydrophobic aggregates. We observed some aggregation of the poly(N,N-dimethylacrylamide) chains containing grafted DO and PY groups in water, which was enhanced by addition of a small amount of SDS. At high surfactant content, SDS micelles encapsulate individual hydrophobic groups, reducing their association. Using equivalent chains, some labeled with PHE and others with AN, we obtained direct proof of the formation of intermolecular aggregates and were able to characterize their evolution in number and size upon addition of SDS. The critical aggregation concentration (CAC) and aggregation number (N agg) of the mixed SDS/polymer micelles are lower than the critical micelle concentration (cmc) and Nagg of SDS in water. This is due to the nucleation effect of the hydrophobic groups grafted to the polymer, which induce the aggregation of SDS at lower concentrations. We determined a lower CAC for the smaller polymer, which has a higher hydrophobic content.