tum size effects and large surface-to-volume ratios make Nanoparticulate TiO 2 -stearate Langmuir-Blodgett-type monothese films interesting for many electrooptical applications, layers and multilayers were directly obtained by using TiO 2 hyand for use as chemical sensors, light-activated catalysts, drosol as the subphase. The surface pressure-versus-surface area solar cells, and other devices (5). Formation of Langmuir isotherms showed that the monolayer could be compressed to a films from nanosized particles on an aqueous solution surmean molecular area of 0.25 nm 2 . The monolayer was transferred face or as the subphase and their layer-by-layer transfer onto onto a CaF 2 or Si substrate at a dipping speed of 18 cm/min and solid substrates by the Langmuir-Blodgett (LB) method has surface pressure of 25 mN/m. It exhibited Y-type multilayer films provided a viable route for the construction of advanced over the range investigated (1-30 layers) with a transfer ratio of materials by colloid chemical methodologies (1,6). This is 1.0 { 0.1. FTIR transmission spectra and linear infrared dichroic spectra provided evidence of the formation of a stable organic/ a kind of LB-type multilayer with nanoparticles inserted inorganic alternating multilayer with nanoparticulate TiO 2 bebetween organic layers. In general, it can be classified into tween the organic monolayers. There is only slight absorption in two kinds of methods. One is called order synthesis, in which the range of the C|O stretching vibration band of the carboxylic Cu 2 S, CdS, CdSe, and PbS are generated in situ between group with the 3-and 6-nm TiO 2 nanoparticles. This means that the polar headgroups from the LB films (7-12). In the other TiO 2 particles are packed closely; i.e., the surface coverage is very method, nanoparticles are inserted between the headgroups high. A possible structure consists of layers of nanoparticles in of LB films. Bawendi and co-workers used a LB technique close-packed form with two stearate ion layers inbetween. But it to deposit monolayers of CdSe nanocrystallites on a surface can be seen that there are some carboxylic groups (1700 cm 01 ) not (13). Fendler and co-workers reported the preparation of a connected to the 20-nm TiO 2 nanoparticle. Electron microscopic TiO 2 monoparticulate layer based on their conception of a (TEM) images of TiO 2 -stearate monolayers show that high-cover-''membrane-mimetic approach to advanced materials'' age monolayers were obtained when the surface pressure increased to 25 mN/m and the dipping speed to 18 cm/min. ᭧ 1997 Academic (14). We have also reported the preparation of a-Fe 2 O 3 -Press stearate alternating LB multilayers by using a monodisperse Key Words: Langmuir-Blodgett method; TiO 2 nanoparticle; innanoparticle a-Fe 2 O 3 hydrosol as the subphase directly (15). organic/organic alternating monolayer and multilayer.
TiO 2 can act as a sensitizer for light-reduced redox processes because of its electronic structure, which is characterized by a filled valence band and an empty conduction band