Formation of BaCrO₄ nanoCrystallites within thermally evaporated sodium bis-2-ethylhexyl-sulfosuccinate and stearic acid thin films

This paper describes the growth of barium chromate (BaCrO₄) nanocrystallites within thermally evaporated thin films of stearic acid (StA) and sodium bis-2-ethylhexyl-sulfosuccinate by a process of Ba²⁺ ion entrapment followed by in situ reaction with CrO₄^2- ions. Dense spherical assemblies of BaCrO₄ nanocrystallites of very uniform size (∼ 50 nm) were obtained within the two different host matrices. The spherical assemblies were composed of smaller (ca. 5-10 nm size) BaCrO ₄ crystals indicating that efficient size control over crystal size may be exercised by the matrix. Contact angle measurements of the BaCrO ₄-StA and BaCrO₄-sodium bis-2-ethylhexyl-sulfosuccinate films indicated that they were hydrophobic, thus pointing to the possible role of hydrophobic interaction between the StA and sodium bis-2-ethylhexyl- sulfosuccinate monolayer-covered BaCrO₄ crystals in the assembly process.