Monolayers structural characterization

Porter M D, Bright T B, Allara D L and Chidsey C E D 1987 Spontaneously organized molecular assemblies. 4. Structural characterization of normal-alkyl thiol monolayers on gold by optical ellipsometry, infrared-spectroscopy, and electrochemistry J. Am. Chem. Soc. 109 3559-68... 

Nuzzo R G, Dubois L FI and Allara D L 1990 Fundamental-studies of microscopic wetting on organic-surfaces. 1. formation and structural characterization of a self-consistent series of polyfunctional organic monolayers J. Am. Chem. Soc. 112 558-69... 

The foregoing discussion has focused on self-assembled monolayers formed on essentially flat electrode surfaces whose areas are vastly larger than those occupied by a single adsorbate. This field has now achieved a significant level of sophistication in terms of their structural characterization as well as their rational design for specific functions, e.g. chemically modulated switches. Although somewhat outside the scope of this book, another important area that exploits the unique properties of self-assembled monolayers is monolayer-protected metal clusters or nanoparticles. 

The purpose of this chapter is to review recent progress in surface structural characterization of select oxide films, with particular emphasis on systems that are sensitive to some of the problems listed above. By thin , we mean a few monolayers up to -1000 A. We take the approach of addressing the issues of oxidation chemistry, either during or after film formation, and lattice and symmetry mismatch with the substrate. We examine representative case studies that illustrate the materials issues listed above. It is assumed that the reader is... 

Caldwell, W. B., Campbell, D. j., Chen, K. M., Herr, B. R., Mirkin, C. A., Malik, A., Durbin, M. K., Dutta, P., and Huang, K. G. A highly ordered self-assembled monolayer film of an azobenzenealkanethiol on Au(Ill) - Electrochemical properties and structural characterization by synchrotron in-plane X-ray-diffraction, atomic-force microscopy, and surface-enhanced Raman-spectroscopy. J. Am. Chem. Soc. 1995 117, 6071-6082 ... 

The book describes the wealth of membrane structures realized by chemists mainly within the last two decades - micelles, vesicles, fibres, and surface monolayers - from the point of view of supramolecular chemistry. It puts new emphasis on "synkinetic" procedures for the preparation of non-covalent assemblies as well as their structural characterization by electron microscopy, solid state NMR spectroscopy, and comparison to X-ray crystal structures. 

A. Tadjeddine, D. Guay, M. Ladouceur, G. Tourillon, Electronic and structural characterization of underpotentially deposited submonolayers and monolayer of copper on gold (111) studied by in situ X-ray-absorption spectroscopy. Phys. Rev. Lett. 66, 2235-2238, 1991. 

The values of Tp, independent of the total amount of PBHB deposited on silica gel t, show that under the layer of isotropic liquid there exists the PBHB structure characterized by the properties different from those of bulk liquid. The surface occupied by a single PBHB molecule in this structure is equal to 1.92 nm. The cross-section of one molecule along its long axis, calculated according to McClellan and Harnsberger [34] is 1.7 - 2.0 nm. Therefore, it seems probable that at 72°C PBHB forms the monolayer composed of flat lying molecules on silica gel surface. 

Booking T., James M., Coster H. G. L., Chilcott T. C. and Barrow K. D. (2004), Structural characterization of organic multilayers on silicon(lll) formed by immobilization of molecular films on functionalized Si-C linked monolayers , Langmuir 20, 9227-9235. 

Yamada, S., Nakano. T., Matsuo, T. Second harmonic generation from Langmuir-Blodgett monolayers of amphiphilic ruthenium(II) complexes structural characterization with polarization measurements. Thin Solid Films 245, 196-201 (1994)... 

Nakano. T.. Yamada. Y., Matsuo, T., Yamada, S. In-situ second-harmonic generation and luminescence measurements for structural characterization of ruthenium-polypyridine complex monolayers with two and four aliphatic tails at the air/water interface. J. Phys. Chem. B 102, 8569-8573 (1998)... 

Fritz, S. E. et ah. Structural characterization of a pentacene monolayer on an amorphous Si02 substrate with grazing incidence x-ray diffraction, J. Am. Chem. Soc., 126, 4084, 2004. 

Fritz, S.E. et al.. Structural characterization of a pentacene monolayer on an amorphous... 

Films or membranes of silkworm silk have been produced by air-drying aqueous solutions prepared from the concentrated salts, followed by dialysis (11,28). The films, which are water soluble, generally contain silk in the silk I conformation with a significant content of random coil. Many different treatments have been used to modify these films to decrease their water solubility by converting silk I to silk II in a process found useful for enzyme entrapment (28). Silk membranes have also been cast from fibroin solutions and characterized for permeation properties. Oxygen and water vapor transmission rates were dependent on the exposure conditions to methanol to facilitate the conversion to silk II (29). Thin monolayer films have been formed from solubilized silkworm silk using Langmuir techniques to facilitate structural characterization of the protein (30). Resolubilized silkworm cocoon silk has been spun into fibers (31), as have recombinant silkworm silks (32). 

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