The structure of ultrathin Langmuir-Blodgett films of cadmium behenate.
Grazing incidence x-ray-diffraction investigations of the structures of Langmuir-Blodgett films of cadmium behenate with 1, 2, 3, 5, and 21 monolayers are reported. The single monolayer film, deposited on a hydrophilic substrate, showed a hexagonal structure, whereas the bilayer film, deposited on a hydrophobic substrate, had a rectangular structure with herringbone orientation of the acyl chains. With multilayer films formed on a hydrophilic substrate, it was possible to detect that the hexagonal structure of the first layer was retained when additional layers were deposited and that the additional layers had the same rectangular structure as the bilayer.
Structure and Elastic Properties of 10−12 Pentacosadiyonic Acid Langmuir Films
Monolayers of the polymerizable 10−12 pentacosadiyonic acid amphiphile spread on a basic buffer are studied both before and after polymerization. We have established the phase diagram of the unpolymerized Langmuir film by isotherm measurements, Brewster angle microscopy, and grazing incidence X-ray diffraction experiments. Diffuse scattering experiments performed at the European Synchrotron Radiation Facility allowed us to investigate the structure and elastic properties of the different monomer phases and the modifications induced by polymerization.
Order–disorder transitions in Langmuir–Blodgett films. III. Polarized Raman studies of cadmium arachidate using integrated optical techniques
Polarized Raman measurements of Langmuir–Blodgett (LB) multilayers of cadmium arachidate (CdA) have been obtained through the application of integrated optical techniques. Excitation of either the transverse electric (TE) or transverse magnetic (TM) mode of an asymmetric slab waveguide was alternately used to produce Raman scattering in the CdA multilayers deposited on its surface. Analysis of the 90° scattered light with a polarizer placed at two mutually perpendicular positions for both the TE and TM modes of the waveguide produced a set of four measurements which were used to determine the orientation and lateral order of the CdA monolayer components. The extent of order in the LB film was then investigated as a function of temperature and compared with that of bulk CdA. The temperature of the order–disorder transition was found to be similar in both cases and consistent with that found previously from infrared studies.