Layer-by-layer self-assembly of organic-organometallic polymer electrostatic superlattices using poly(ferrocenylsilanes)

Water-soluble poly(ferrocenylsilane) (PFS) and poly(styrenesulfonate) (PSS) of alternating charge are shown to self-assemble in a layer-by-layer fashion on primed Au, Si, and quartz substrates to create the first examples of organic-organometallic electrostatic superlattices from polymers with ferrocene units in the backbone. The layer-by-layer assembly of these electrostatic superlattices has been monitored through frequency changes with layer deposition using a quartz-crystal microbalance (QCM), a regular film thickness increase observed using ellipsometry, and step-wise absorbance increases observed using ultraviolet-visible (UV-vis) spectroscopy. As well, structural information was obtained using X-ray photoelectron spectroscopy (XPS), water contact angle measurements, and atomic force microscopy (AFM). These superlattices are of interest as possible precursors to patterned magnetic and redox active multilayers.