Formation of langmuir‐blodgett films containing two‐dimensional monoatomic arrays of rare‐earth cations

The work is focused on the preparation and characterisation of rare‐earth containing stearic acid Langmuir‐Blodgett (LB) films. Stearic acid monolayer behavior on the rare‐earth containing aqueous subphase have been analyzed by thermodynamic measurements. The compression isotherm shape changed substantially under varying the anion type at the constant rare‐earth cation content in aqueous subphase. The structure of formed multilayer rare‐earth containing LB films was studied using small angle X‐rays diffraction. The considerable structural defects in multilayer films were found when rare‐earth chloride solution was exploited as aqueous subphase, caused presumably by electrostatic interactions at the monolayer surface under high binding of rare‐earth cations. The use of monodentate complexones like acetic acid was proposed to form bulk phase quasi‐neutral rare‐earth complexes. The electroneutral ligand exchange reactions of such complexes with stearic acid monolayer allowed to neutralise monolayer surface under rare‐earth cations binding and to form condenced monolayer below the triple‐point temperature. The compression of such monolayer to the state of minimal compressibility and subsequent monolayer deposition resulted in the formation of high ordered LB films with high content of adsorbed multivalent rare‐earth cations arranged in two‐dimensional monoatomic arrays.