Colloids and Surfaces A

Reactions of complex ions of platinum and palladium in Langmuir-Blodgett films of dimethyldioctadecylammonium chlorometallates

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Langmuir-Blodgett films containing complex ions of platinum(II), platinum(IV) and palladium(II) were prepared from compressed monolayers of dimethyldioctadecylammonium bromide on subphases of these ions. The films were characterized by measuring the surface pressure vs. area per molecule ( π A) isotherms and by UV/visible spectroscopy, grazing angle FTIR spectroscopy and X-ray photoelectron spectroscopy. The reactions of these films with H2S and hydrazine were investigated by the above spectroscopic techniques and by atomic force microscopy (AFM). The absorbance onsets of the H2S-exposed films are dramatically blue shifted relative to the bulk bandgaps of PtS2, PtS and PdS. This is consistent with the formation of particles in the "Q state" size regime. AFM images of hydrazine-treated (DDA)2(PdCl4) films on mica revealed metal particles with an average diameter of 3.6 nm. © 1995.