Multilayers layer structure determination

With the appropriate fiber-optic probe and data processing techniques, UV-vis spectroscopy may be used to determine the optical thickness of a transparent thin film. It is possible to simultaneously measure thickness of different layers in a multilayer structure as long as each layer falls within the analysis range of the instrument. Typically, this means layers in the 0.5-150/rm range. A further constraint on this technique is that the layer structure of the film must be smooth on the scale of the spot size of the fiber-optic probe. Neighboring layers must have different indices of refraction in order for them to appear as distinct layers to the analyzer. 

In order to make meaningful physical measurements on monolayer and multilayer L-B films, it is essential that the films be characterized to determine the molecular structure, unformity of the film and layer-to-layer structural correlation. To probe the molecular structure, our research group has utilized a variety of spectroscopic techniques such as u.v.-visible spectroscopy, ATR-IR, wave-guide Raman, surface-plasmon wave Raman spectroscopy and inelastic electron tunneling. The spectroscopic techniques... 

Because of their easy handle Langmuir-Blodgett multilayers are best suited for a characterization of the diyne polymerization in lipid layer structures. The built-up layers consist of monolayers successively deposited on substrates, the number of layers being determined by the number of dipping cycles of the substrate >. The method however is restricted to amphiphiles that are able to form highly stable, solid-condensed films at the air-water interface. 

The manufacturing of adaptive structures requires new production methods that need a lot of experience and expertise for the fabrication of complex systems with embedded or applied actuators and sensors. Patch-like sensors such as 1-3 piezo fiber composites are quite appropriate to be attached to the surface or to be integrated into lightweight multilayer constructions. The bond layer between the piezo element and the base structure determines the transfer behaviour of strain, vibrations and acoustic waves from the actuator to the structure and from the structure to the sensor. Local stress distributions can strongly be influenced by the bonding technique. 

These presumptions are based on the results of chanical composition analyses and structural determinations by beam-based analytical methods. To verify the mechanisms involved, it is essential to clarify the frictional and mechanical properties of each layer in the multilayered structure of the tribofilm. Most importantly, with respect to the uppermost surface and the underlying area, which are thought to control the macroscale friction behavior, it is indispensable to determine differences not only in surface roughness, but also in shear strength and frictional behavior relative to depth on a nanometer scale. It is also important to make clear the distribution of the chemical composition relative to the tribofilm depth and to make this chemical distribution consistent with the nanometer-scale frictional and mechanical properties. However, estimating these properties experimentally on a nanometer scale is a difficult task, although several attempts have been made [24-28],... 

Worthington, C. R., King, G. I., McIntosh, T. J. Direct Structure Determination of Multilayered Membrane-Type Systems Which Contain Fluid Layers. Biophys. J. 13,... 

Equations la and lb are for a simple two-phase system such as the air-bulk solid interface. Real materials aren t so simple. They have natural oxides and surface roughness, and consist of deposited or grown multilayered structures in many cases. In these cases each layer and interface can be represented by a 2 x 2 matrix (for isotropic materials), and the overall reflection properties can be calculated by matrix multiplication. The resulting algebraic equations are too complex to invert, and a major consequence is that regression analysis must be used to determine the system s physical parameters. ... 

The CgQ surface coverage was determined to be 2.0 10 mol cm . The monolayer can be further modified with monomeric amine reagents, which demonstrates the potential of the self-assembly process for growing three-dimensional fullerene structures. Different surfaces such as quartz. Si-oxide [105] or ITO [102] were coated with multilayers of fullerene up to stacks of 9 layers. An imidirectional electron transfer is possible across the fullerene mulhlayers [102]. Not only can multiple layers of fullerenes be connected to a certain surface but amino-functionalized can also serve as a linker between two different surfaces. 3-Aminopropyl-tethered glass plates could be linked via a Cgg layer to 3-aminopropyl covered zeolite crystals [106]. 

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