Biomimetic formation of thin, coherent iron oxide films under Langmuir monolayers

This study focuses on the biomimetic formation and growth of thin iron oxide films under Langmuir monolayers. These coherent film structures were formed in the presence of different iron chloride solutions during the addition of an ammonia atmosphere. Stearic acid, stearyl amine and stearyl alcohol were used as film forming surfactants while the subphase contained FeCl2, FeCl3 or a mixture of both salts. The thin, coherent films consisted of X-ray amorphous iron oxide, hydroxide or oxyhydroxide. The films were studied by scanning electron microscopy, atomic force microscopy, X-ray diffraction, dynamic light scattering and surface potential measurements. Based on the experimental results we propose a growth mechanism that is guided by the formation of nanoparticles in the subphase and their assembly and aggregation underneath the Langmuir films.