Preparation and characterization of redox cellulose Langmuir-Blodgett films containing a ferrocene derivative

The 3-ferrocenoylpropanoyl group, one of the redox species, was introduced at C-2 and/or C-3 positions of 6-O-(4-stearyloxytrityl)cellulose. The spreading behavior of the cellulose derivatives on the water surface and the properties of Langmuir-Blodgett (LB) films were investigated. The surface pressure-area isotherm of the cellulose monolayer was changed by the subphase temperature. Uniform monolayers of 6-O-(4-stearyloxytrityl)cellulose 3-ferrocene propionate (STCFc) could be deposited successively onto several substrates by the horizontal lifting method at 10 mN m(-1), and this produced X-type LB films. The successive uniform depositions of STCFc were confirmed by ultraviolet-visible absorption spectra. X-ray diffraction measurements indicated that the thickness of the STCFc molecules in the LB films was 1.99 nm. Fourier transform infrared spectroscopy measurements supported the idea that hydrocarbon chains in the LB films were highly ordered (trans-zigzag) and oriented considerably perpendicular to the surface of the substrate. Moreover, the C=O group of the ferrocenoyl groups was perpendicular to the surface of the substrate, and the ferrocene group was occupied in the water phase. Cyclic voltammograms for the STCFc monolayer on a gold electrode exhibited surface waves. The interfacial electron-transfer process between the redox site incorporated into the cellulose LB monolayer and the electrode surface was fast enough at a scanning rate lower than 100 mV s(-1). (c) 2005 Wiley Periodicals, Inc.