Abstract
To investigate bilayer structures of amphiphilic compounds based on X-ray diffraction data, the method of analysis was designed and programmed for the computer calculation. In order to verify this program, it was applied to the analyses of wholly synthetic amphiphiles whose bilayer structures were determined precisely by X-ray single crystal analyses. The result shows that the program is very effective for investigating molecular aggregation states, especially when there are enough number of reflections which have information about a repeating period of a bimolecular layer. Since many amphiphilic compounds have only small number of flexible parts of their molecular conformation in a gel state, the important parameters for the molecular packing in a bilayer structure are not those regarding the molecular conformation, but the inclination angle of the molecule to the bilayer surface and the translation of the molecule along the direction normal to the surface. The agreement between calculated and observed structure amplitudes is very sensitive to these two parameters.
This program is applicable to the structure analyses of crystalline powder, casting films and Langmuir-Blodgett films of amphiphilic compounds, but cannot be applied to those of X- and Z- built-up films because of their non-centrosymmetric structures.
