Iron sulphide formation in the ferric stearate Langmuir-Blodgett films

Ferric stearate (FeSt) Langmuir-Blodgett (LB) films have been reacted chemically with H₂S gas for making iron sulphide within the organic matrix. Films, before and after the reaction with H₂S, have been analyzed with the X-ray reflectivity (XRR), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) studies. After sulphidation, more ‘pinhole’ defects form which changes the film morphology and the number of layers increases due to the rearrangement of the molecules. Formation of less ordered iron sulphide within the stearic acid multilayers after sulphidation increases the interfacial roughness that decreases the reflectivity. XPS analysis shows that polysulphide forms within the microenvironment of the FeSt LB films after reaction with H₂S whereas both mono and polysulphide are produced when the reaction occurs with FeSt in bulk.