Synthesis and self-assembly of poly(ferrocenyldimethylsilane-b-2-vinylpyridine) diblock copolymers

A new class of metal-containing diblock copolymers, PFS-b-P2VP (PFS = poly(ferrocenyldimethylsilane), P2VP = poly(2-vinylpyridine)), with a hydrophobic organometallic block and a highly polar hydrophilic organic block were synthesized via 1,1-dimethylsilacyclobutane (DMSB)-mediated sequential anionic polymerization. In the bulk state, PFS-b-P2VP copolymers with a volume fraction of PFS close to 0.20 give a morphology with cylindrical domains of PFS. A remarkable difference in the morphology of PFS-b-P2VP micelles was observed depending on the nature of selective solvent. Simply by using different alcoholic solvents either spherical or cylindrical micelles can be selectively formed from the same copolymer. WAXS experiments indicate that the crystallinity of the core-forming PFS block may be responsible for this difference.