Langmuir-Biodgett Films-Self-Organized Hybrid Nanocomposites

METALLOPOLYMERIC LANGMUIR-BIODGETT FILMS—SELF-ORGANIZED HYBRID NANOCOMPOSITES 

Metal-containing nanoparticles inserted into LB films (LBFs) belong to yet another promising class of precursors for the preparation of nanocomposites. Procedures to synthesize of self-organized inorganic surfactant composites have recently been developed. This has made possible the preparation of new 2D composite materials. Generally, the phase sizes within these materials are no more than 2-10 run. 

Two procedures for the formation of nanosized particles within these films are employed. The first procedure combines the principles of colloid chemistry, selforganization and the growth of monolayers. The formation of nanosize particles is performed in the presence of stabilization agents and components forming LBFs. Chemical and photochemical reduction of metal salts in aqueous solutions can cause particle formation. The resulting layers act as specific templates. This approach is also of interest in studies of biomineralization, including studies using the sol-gel method. 

The second procedure consists of LBF deposition on the surface of stabilized nanosize particles followed by insertion of these particles into polylayers. Fimctional groups participate, including groups on inorganic layers. For example, a LBF based on amphiphilic Ru complexes was immobilized on a monolayer of hectorite. Lamellar films and polylayers were formed. LBFs with a specified organization were formed either directly on the surface of colloidal particles or on the water surface. Then 

Multilayer LBFs are often prepared from cadmium stearate, magnesium stearate, and a-Fe203. Self-organized films of silver stearate (8-14 layers) were formed in hydrophobic layers of stearic acid. The film was transferred to electrodes (n = 25 mN m ) and then electrochemically reduced in a neutral or acidic solution to form 2D Ag clusters (20-30 nm). These films also contained Ag clusters of the sandwich type. Self-organized metal-containing LBF ensembles are often rrsed for 

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X. METALLOPOLYMERIC LANGMUIR-BIODGETT FILMS— SELF-ORGANIZED HYBRID NANOCOMPOSITES... 

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