Structure and thermal stability of cadmium arachidate/poly(tert-butyl methacrylate) alternating Langmuir–Blodgett film

Layer structure and thermal stability of alternating Langmuir–Blodgett (LB) films of cadmium arachidate (CdA 2 ) and poly( tert -butyl methacrylate) (PtBMA) was investigated by X-ray reflection and in-plane diffraction study. The LB films were deposited on hydrophobically pre-treated silicon wafer surface and the polymer layers are inserted between CdA 2 bilayers. Layer spacing of the alternating LB film increases linearly by 9.8 A per PtBMA layer, which is consistent with the single layer spacing of homo-PtBMA LB film. Lateral lattice structure of CdA 2 in alternating LB films maintains its hexagonal packing structure as found in CdA 2 monolayers while the multilayer CdA 2 LB film is known to change its structure from hexagonal to orthorhombic lattice. Therefore, the polymer layers inserted between CdA 2 bilayers in the alternating LB films effectively prevent the CdA 2 film not only from the growth of defect but also from the formation of three-dimensional crystallites of CdA 2 . In addition, the hexagonal packing structure of CdA 2 bilayer was maintained up to 90°C while the molecular area increases slightly.