Synthesis and Self-Assembly of the Organic−Organometallic Diblock Copolymer Poly(isoprene-b-ferrocenylphenylphosphine): Shell Cross-Linking and Coordination Chemistry of Nanospheres with a Polyferrocene Core

Narrow polydispersity samples of the organic-organometallic diblock copolymer, poly(isoprene- b -ferrocenylphenylphosphine) (PI- b -PFP), have been synthesized by sequential living anionic polymerizations in tetrahydrofuran. These block copolymers form “starlike” spherical micelles in hexane with a dense PFP core surrounded by a swollen corona of PI chains as characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS) measurements. Although the TEM results indicated a very narrow micelle core size distribution, DLS studies indicated a monomodal, but relatively broad distribution of the overall hydrodynamic size of the micelles in solution. The hydrodynamic size of the micelles and the broad size distribution in solution suggest that DLS measurements might be detecting aggregates of individual micelles. The PI corona chains were found to undergo a cross-linking reaction under UV irradiation in the presence of the radical initiator AIBN. The micelle solution concentration and UV irradiation time affect this cross-linking reaction. Furthermore, the phosphorus sites in the block copolymers could be coordinated to a transition metal, such as Au. The resulting Au-containing block copolymers still form spherical micelles, but with a different size and size distribution.