Toward an easy access to dendrimer-like poly(ethylene oxide)s

Dendrimer-like poly(ethylene oxide)s (PEOs) were synthesized by an iterative divergent approach combining anionic polymerization of ethylene oxide from multi-hydroxylated precursors and branching reactions of PEO chain ends. Partial deprotonation of the hydroxyls (< 30%) and use of dimethyl sulfoxide as solvent proved crucial for a "controlled/living" polymerization of ethylene oxide at room temperature. These sequences of reactions allowed us to prepare a dendrimer-like PEO up to the eighth generation with a molar mass of 900 000 g mol(-1) and 384 external hydroxyl functions. All samples from generation 1 to 8 were characterized by 1H NMR spectroscopy, light scattering, and viscometry. The evolution of the intrinsic viscosity versus the generation number of these dendrimer-like PEO is similar to that of regular dendrimers.