Langmuir-blodgett films prepared from ferroelectric lead zirconium titanate particles

The preparation of monoparticle-thick Langmuir films from 70-nm, lauric acid-coated (dispersion I) and alcohol-coated (dispersion II) ferroelectric lead zirconium titanate (PZT) particles is described. Surface pressure (II) vs surface area (A) isotherms, in situ on the water surfaces, atomic force microscopic (AFM), and electron microscopic (TEM) images, ex situ after their transfer to substrates, established the presence of monoparticles with appreciable and variable interparticle distances (dispersion I) and relatively densely packed monoparticles (dispersion II) in the Langmuir films. Langmuir-Blodgett (LB) films were formed by the monoparticulate layer by monoparticulate layer transfer of the PZT film to substrates (glass slides coated by 500-A gold or indium tin oxide). Good transfer ratios (up to eight layers) were obtained if each transferred PZT film was fixed by a methanol:ethanol:2-propanol solution of lead(II) acetate, zirconium(IV) butoxide, and titanium-(IV) isopropoxide taken in stoichiometric amounts for Pb(Zr_0.5Ti_0.5)O and cured at 80°C for 1.5 min. Ferroelectric properties of the LB films, prepared from dispersion II, have been demonstrated by polarization measurements using a Sawyer-Tower circuit.