Poly(ferrocenylsilane) Gels and Hydrogels with Redox-Controlled Actuation.

This concise paper discusses poly(ferrocenylsilane) (PFS)-based organometallic gels and hydrogels as a novel class of redox-responsive materials. First, the use of silicon-bridged spirocyclic [1]ferrocenophane crosslinkers for creating PFS networks swellable in organic solvents is described. Optical properties of PFS composite colloidal crystal films, composed of monodisperse silica spheres embedded in such PFS networks, are shown to be influenced by solvent swelling or redox chemistry, allowing the use of these composites in photonic crystal full-color displays. The synthesis of networks composed of water-soluble PFS polyanions or polycations is discussed. In response to redox stimuli, a polyanionic PFS-hydrogel exerted a pressure, which could render it useful as an actuator.