Modelling, Langmuir-Blodgett films

Langmuir-Blodgett films (LB) and self assembled monolayers (SAM) deposited on metal surfaces have been studied by SERS spectroscopy in several investigations. For example, mono- and bilayers of phospholipids and cholesterol deposited on a rutile prism with a silver coating have been analyzed in contact with water. The study showed that in these models of biological membranes the second layer modified the fluidity of the first monolayer, and revealed the conformation of the polar head close to the silver [4.300]. 

S. Zhao and W. M. Reichert, Modeling of fluorescence emission from cyanine-dye-impregnated Langmuir-Blodgett films deposited on the surface of an optical fiber, Thin Solid Films 200, 363-373... 

Amino-5-nitropyrimidine, cocrystallization, 455 Amorphous polymers, criteria for use in second harmonic generation, 250-251 Amphiphilic molecules polar Z-type Langmuir-Blodgett films, formation, 473-479 structures, transfer behavior, and contact angles, 474,476-477r Anharmonic oscillator models, nonlinear optical effect-microstructure relationship, 361... 

This simple model is sufficient to reproduce properties such as crystal structure, vibrational frequencies, dispersion curves, and elastic constants [40-43], These calculations were applied also to other organized media such as monolayer gaseous films on graphite [44,45], liquid crystals, and Langmuir Blodgett films. 

Langmuir-Blodgett Films as Model Systems in Basic Research... 

This paper presents studies of solid state polymerization aimed towards formulating a dynamic model of reactivity in the condensed phase. Phonon spectroscopy is successfully used to elucidate the mechanism of lattice control of the reaction. Novel concepts of phonon-assisted thermal and photochemical reactions are introduced, supported by experimental data. Non-linear laser spectroscopy is used to find the importance of biexcitonic processes in photopolymerization. Also, spectroscopic studies of reactions in Langmuir-Blodgett films and at gas-solid interface which produce ordered polymers are presented. 

Axis Model Applied to Langmuir-Blodgett Film.348... 

Fig. 7. Plots for the absorbance of the mixed Langmuir-Blodgett film ofall-fro/w-)3-carotene with barium stearate (1 10) detected on irradiation with 445 nm light at any incident angles. Filled circles represent the results obtained on irradiation with s-polarized light. Solid lines show the results ofthe theoretical calculations based on the axis model assuming n= 1.46 and Q./C = 0.5...

Combined with some simple symmetry arguments applicable to infinite-stack systems with regular structures, the dimeric models provide us with a set of selection rules and spectral predictions that make infrared and Raman spectoscopy a powerful tool for structural investigations. These methods become rather unique if one considers the widespread availability of the required instrumentation and their applicability to disordered and amorphous materials like, e.g., thin films and Langmuir-Blodgett films which are more apt for applications than crystalline materials. 

Fig. 5 Schematic model of (a) palmitoyl cellulose Langmuir-Blodgett films and (b) stearic acid Langmuir-Blodgett films on the ITO substrate.

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