Study On Synthesis, Characterization, Cross-linking Reaction And Properties Of Novel Ferrocene-based Polymers

Ferrocene-based polymers have emerged as an important category of functional polymer with unique electrical, optical and magnetic properties. Considerable attention was paid to development of these polymer systems, which were useful materials for modification of electrodes, as electrochemical sensors and as nonlinear optical materials. In this paper the synthesis, property and application of ferrocene-based polymers were reviewed. A series of novel ferrocene-based polymers were synthesized and characterized, and used as doping conducting materials, self-assembly materials and photoresist. The electrochemistry properties and the mechanisms of doping conductivity and self-assembly were discussed. The main conclusions are listed as follows.In this paper, two series of poly(ferrocenylsilanes) (PFS) including polyferocenyldimethylsilane (PFDMS) and polyferrocenylmethylphenylsilane (PFMPS) were prepared. The influences of polymerization time, polymerization temperature, and monomer purity on polymer molecular weight and polydispersity were discussed. It was found that molecular weight of PFDMS could be increased by prolonging the polymerization time, but this method had no effect on molecular weight of PFMPS. Solubility, crystallizability and filming properties of PFS were investigated, and the process to obtain controllable PFS films was built up. PFS films were doped by saturated iodine solution in hexane. By the UV/Vis investigation, it was found that the electronic structure change of PFS was attributed to electron transfer between iodine and ferrocenic units at PFS. The charge transport properties of PFS films were tested by Van de Pauw techniques, and it was found that the conductivity σ, carrier density R_H+ and mobility μ. of films were 2.08×10^-3 /(cm·Ω), 2.55×10¹³ /cm³ and 170 cm²/(V'S) respectively after the films were doped for 5 hr. The possible conducting mechanisms were discussed.In this paper, five kinds of ferrocene-based polymers including poly(ferrocenylmethylchloro-silane) (PFMCS), poly(boraferrocene) (PBF), poly(ferrocenylmethylbutylsilane) (PFBMS), methoxyl- and butyl-substituted PFS (MeO-Bu-PFS) and naphthylethoxyl- and butyl-substituted PFS (Np-Bu-PFS) were synthesized, and PFBMS, MeO-Bu-PFS and Np-Bu-PFS were reported first. By investigation into electrochemistry in polymer solution, it was found that the fluctuation of solution ohmic potential iR did not affect the compensated cyclic voltammograms (CV), and CH₂Cl₂ was the optimal solvent during PFS electrochemistry investigation due to its moderate dielectric constants (ε), low viscosity factors (η) and small iR. In electrochemistry the properferrocene-based polymer concentration was lower than 3.0 mM. In solution, PFS were oxidized gradually and electrodeposited on the electrode surface. The electrochemical behaviors of ferrocene-based polymer solution were affected by variable, substitution group and atom bridge. The apparent diffusion coefficients of PFS with the different molecular weight were 10^-7～10^-5 cm²/s according to calculation.In this paper, six kinds of methacrylate-based PFSs including methacrylate-substituted PFS (HEMA-PFS), methoxyl- and methacrylate-substituted PFS (MeO-HEMA-PFS-a and MeO-HEMA-PFS-b), naphthylethoxyl- and methacrylate-substituted PFS (Np-HEMA-PFS), 2,2,6,6-tetramethyl-1-piperidinyloxy- (TEMPOL) and methacrylate-substituted PFS (TEMPOL-HEMA-PFS) and butyl- and methacrylate-substituted PFS (Bu-HEMA-PFS) were prepared, and Np-HEMA-PFS, TEMPOL-HEMA-PFS and Bu-HEMA-PFS were reported first. By investigation into UV/Vis spectra of methacrylate-based PFS solution, the characteristic peaks could be modulated by different quantitative methacrylate groups and different substitution groups on Si. The CV of methacrylate-based PFS were affected by different quantitative methacrylate groups and different substitution groups on Si, and it was found that the Fe-Fe interaction in PFS could be modulated by different quantitative methacrylate groups and different substitution groups on Si too. A novel photoresist based on methacrylate-substituted PFS was prepared, and polymer films were photopatterned by photolithography process. The self-assembly behaviors of methacrylate-based PFSs (HEMA-PFS, MeO-HEMA-PFS-a, MeO-HEMA-PFS-b and Np-HEMA-PFS) in mixture solvents were investigated. It was found that the self-assembly behaviors were affected by PFS concentration, composition of solvents, aging time and so on. In mixture solvents HEMA-PFS, MeO-HEMA-PFS-a and Np-HEMA-PFS could self-assembl into nanoparticles with hollow cores, and MeO-HEMA-PFS-b could self-assembl into flower-like large-compond-capsules. Photo-cross-linking of self-assembled particles from PFS with various methacryiate side group numbers afforded core-shell nanoparticles by adding photoinitiator, irradiating and aging, and these particles proved to be stable.