Synthesis and self-assembly of structurally well-defined polyferrocenylsilanes and their block copolymers.
Published: 2006
Language: eng
Number of pages: 188
ISBN-13: 9780494217849
Description: Block copolymers of poly ferrocenylsilanes (PFSs) and polypeptide were synthesized by the ring-opening polymerization of strained [1]-silaferrocenophanes and alpha-amino acid-N-carboxyanhydrides (alpha-NCA). PFS-b-poly(gamma-benzyl-L-glutamate) (PFS- b-PBLG) block copolymers showed thermotropic liquid crystalline phases. The benzyl ester groups of poly(gamma-benzyl-L-glutamate) were deprotected under standard hydrogenation conditions, and the resulting amphiphilic block copolymer, PFS-b-poly(L-glutamic acid), formed micelles in water.Dendronized polyferrocenylsilanes were synthesized by a substitution reaction of reactive poly(chloromethylferrocenylsilane) with monodendrons with a focal hydroxy group. AFM studies of the fractionated high molecular weight PFS samples revealed a spherical cocoon structure for the single chains of the dendronized polymer as well as elongated single chain structures.Thermoreversible gelation of PFS-b-PBLG in toluene was observed. Organogels of PFS-b-PBLG were studied by transmission electron microscopy (TEM), atomic force microscopy (AFM), and small-angle X-ray scattering (SAXS). Based on the experimental results, a new mechanism for the self-assembly was proposed to explain the gelation of these PBLG block copolymers. This mechanism is likely to be general for numerous block copolymers based on helical polypeptides.Diblock copolymers, poly isoprene-b-polyferrocenylsilane (PI-b-PFS), were synthesized by living anionic polymerization. The PI block formed in cyclohexane showed a high content of 1,4-cis -microstructure rather than 1,2- or 3,4-microstructure. The micellization behavior of these block copolymers in hexane and decane (selective solvents for the PI block) was studied by TEM, and comparisons were made between polymers with high and low 1,4-cis-microstructure contents.New macromolecular self-assembling building blocks, dendron-helical polypeptide copolymers and dendritic-helical copolypeptides, have been synthesized. These materials possess a well-defined 3-D shape and self-assemble in solution to form nanoribbons via a mechanism proposed in this thesis. The well-defined 3-D structures of these macromolecular building blocks also affect their self-assembly behavior such as a lyotropic liquid crystal formation in organic solvents and micellization in water.Redox-active ferrocene groups were incorporated in conjugated polymer backbones. The resulting polymers with bissilylferrocenyl moieties showed photoluminescence triggered by the oxidation of ferrocene groups in the main chain. The intensity of the luminescence increased with increasing extent of oxidation of ferrocene groups in the polymer backbone. The polymer containing ferrocenyl groups in the backbone showed photovoltaic properties upon illumination.
Notes: Source: Dissertation Abstracts International, Volume: 68-01, Section: B, page: 0315.

Advisors: Mitchell Winnik and Ian Manners.

Thesis (Ph.D.)--University of Toronto, 2006.

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