Redox-active mesomorphic complexes from the ionic self-assembly of cationic polyferrocenylsilane polyelectrolytes and anionic surfactants

Abstract

The concept of ionic self-assembly (ISA) has been employed to design and prepare new redox-active thermotropic liquid-crystalline materials. These ordered anisotropic materials in the bulk state were constructed from the complexation of a series of polyferrocenylsilane (PFS) polyelectrolytes with several oppositely charged surfactants. The structural characterization of the self-assembled materials was performed using a variety of techniques including FTIR, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), polarized optical microscopy (POM), small- and wide-angle X-ray scattering (SAXS and WAXS), transmission electron microscopy (TEM) and UV-vis spectroscopy. Results showed that strong coulombic attractions between the starting building blocks resulted in the formation of ordered mesostructures with average periodicities of 2–3 nm. The precise phase thickness of both the PFS and surfactant layers was quantitatively determined using a one-dimensional correlation function. Moreover, the redox properties of the mesomorphic organometallic PFS polyelectrolyte–surfactant complexes were systematically investigated using cyclic voltammetry (CV) and chemical redox methods. The versatility of this ISA technique also allowed the incorporation of a photoactive azobenzene-containing surfactant, resulting in ordered mesostructures with potential optoelectronic applications.