The "living" free radical synthesis of poly(4-hydroxystyrene): Physical properties and dissolution behavior

The synthesis of a range of narrow polydispersity, well-defined poly(4-hydroxystyrene)s via a "living" radical polymerization technique is reported. The synthetic route chosen involves the 2,2,6,6-tetramethyl-1-piperidinyloxy mediated free radical polymerization of acetoxystyrene, followed by deacetylation with base. The efficiency and molecular weight control of the "living" free radical polymerization of 4-acetoxystyrene is compared to styrene. Further, the effect of initiating system, "unimolecular" or "bimolecular", on the "living" radical polymerization of 4-acetoxystyrene is also discussed. The physical and structural properties of these well-defined polymers were used to compare poly(4-hydroxystyrene) prepared via "conventional" free radical polymerization. A fundamental study of the dissolution of poly(4-hydroxystyrene) in aqueous base was undertaken to elucidate the effect of polydispersity, molecular weight, and structure on the dissolution behavior of these polymers.