Molecular arrangement characteristics of a pyrrole-containing arachidic acid LB film

The transformation of the molecular arrangement of an arachidic acid (C₂₀) Langmuir-Blodgett (LB) film was studied with an increase of pyrrole (Py) quantity which we used as guest molecules to the host molecules, C₂₀. The change of molecular occupation area of a C₂₀ LB film was estimated by π-A curves, a quartz crystal microbalance method and friction force microscopy (FFM). It was found that a C₂₀ LB film can contain Py molecules 1.4 times as large as C₂₀ molecules. The observation by FFM showed the enlargement of the occupation area of C₂₀ upon addition of Py, however, the molecules of C₂₀ do not change the internal structure of the film upon compression. The experimental results show that the lattice constant of a C₂₀ LB film is easy to control by the quantity of Py molecules contained in the LB film.