Synthesis of meth(acrylate) diblock copolymers bearing a fluorescent dye at the junction using a hydroxyl-protected initiator and the combination of anionic polymerization and controlled radical polymerization

The synthesis of well-defined poly(methyl methacrylate)-b-poly(alkyl acryla te) diblock copolymers with a single fluorescent dye molecule (phenanthrene or anthracene) at the junction was investigated. The first block was prepa red by the anionic polymerization (AP) of(meth)acrylate in THF at -78 degre esC, using the 3-(tert-butyldimethylsilyloxy)-1-propryl (aryl = 2-phenanthr yl or 2-anthryl) monoadduct as the initiator. After the end group of the fi rst block was transformed into alpha -bromoester, the diblock copolymer was formed by the atom transfer radical polymerization (ATRP) of the second me thacrylate monomer using the first block as the initiator. The block copoly mers were characterized by GPC, UV, and NMR. We found that the synthesis of anthracene-labeled diblock copolymer was perturbed by the reaction of the propagating poly(alkyl acrylate) radical with anthracene. Consequently, thi s synthesis has to start from the anionic polymerization of tert-butyl acry late, followed by chain extension to poly(methyl methacrylate) by ATRP.