Free radical homopolymerization, in heterogeneous medium, of linear and star-shaped polymerizable amphiphilic poly(ethers): A new way to design hydrogels well suited for biomedical applications

The synthesis and the properties of selected macromolecular structures base d on poly(ethylene oxide), (PEO) are discussed in the present paper. The fi rst part deals with the development of efficient multifunctional anionic in itiators aimed to design well-defined functionalizable star-shaped PEO's. D ifferent approaches providing access to branched species of controlled hydr ophilic /hydrophobic balance will be considered. The second part is devoted to the homopolymerization of amphiphilic bifunctional PEO macromonomers as an efficient way to yield PEO hydrogels directly in water. The extension o f that approach to degradable PEO hydrogels or to the copolymerization of m acromonomers with star-shaped PEO's partially functionalized with polymeriz able entities will be briefly mentioned. These hydrogels served as semiperm eable membrane for an artificial pancreas and as a template for the growth of nervous cells.