Organic Langmuir-Blodgett

Well organized Langmuir-Blodgett (LB) films have been obtained from mixtures of a push-pull carotenoid and co-tricosenoic acid as shown in 7. These mixed films exhibit a very good cohesion, with an area of about 25 A2 per carotenoid molecule. They can easily be transferred onto solid substrates. Examination by UV-visible linear dichroism measurements confirms that the carotenoid chains are oriented perpendicularly to the surface of the substrate in card-packed aggregates, in which the polyenic chains interact via excitonic coupling, as indicated by the large hypsochromic shift of the tc-tc transition (20). 

Figure 14.2.1 Examples of specific adsorption on electrodes, (a) Adsorption of (1) a disulfide or protein on Hg (2) an olefin on Pt (3) an organized Langmuir-Blodgett film on Au. (b) Adsorption of a metal ion or complex through an anionic ligand bridge. [From A. J. Bard, Integrated Chenucal Systems, Wiley, New York, 1994, with permission.]...

Silerova(Back) R, Kalvoda L, Neha- D, Ferencz A, Wu J, Wegner G (1998) Electrical conductivity of highly organized Langmuir-Blodgett films of phthalocyaninatopolysiloxane. Chem Mater 10 2284-2292... 

A. Ulman, An Introduction to Ultrathin Organic Films From Langmuir-Blodgett to Self-Assembly, Academic, New York, 1991. 

C2.4 Organics films (Langmuir-Blodgett films and self-assembled monolayers)... 

The expectation of the structural dependence of lubrication motivated great numbers of investigations that intended to prepare and use highly ordered organic films, such as the Langmuir-Blodgett (L-B) hlms and Self-Assembled Monolayers (SAMs), as solid lubricant, which will be discussed more specihcally in Section 4. 

A large number of potential applications for organized protein monolayers have recently motivated considerable research activity in this field (Boussaad et al. 1998, Kiselyova et al. 1999). Construction of specific interaction-directed, self-assembled protein films has been performed at the air-water interface. The Langmuir-Blodgett (LB) technique has been extensively used to order and immobilize natural proteins on solid surfaces (Tronin et... 

The Langmuir-Blodgett (LB) technique was successfully applied for the deposition of thin protein layers (Langmuir and Schaefer 1938, Tiede 1985, Lvov et al. 1991). LB organization of protein molecules in film not only preserved the structure and functionality of the molecules, but also resulted in the appearance of new, useful properties, such as enhanced thermal stability (Nicolini et al. 1993 Erokhin et al. 1995). 

FIG. 1 Geometries of electrolyte interfaces, (a) A planar electrode immersed in a solution with ions, and with the ion distrihution in the double layer, (b) Particles with permanent charges or adsorbed surface charges, (c) A porous electrode or membrane with internal structures, (d) A polyelectrolyte with flexible and dynamic structure in solution, (e) Organized amphophilic molecules, e.g., Langmuir-Blodgett film and microemulsion, (f) Organized polyelectrolytes with internal structures, e.g., membranes and vesicles. 

The very popular applications of the adsorption potential measurements are those dealing with the surface potential changes at the water-air and water-hydrocarbon interfaces when a monolayer film is formed by an adsorbed substance. Phospholipid mono-layers, for instance, formed at such interfaces have been extensively used to study the surface properties of the monolayers, which are expected to represent, to some extent, the surface properties of bilayers, and biological, as well as various artificial membranes. An interest in a number of applications of the ordered thin organic films, e.g., Langmuir-Blodgett layers, dominated the insoluble monolayer research activity during the last decade. 

Ray, K. and T. N. Mishra. 1997. Photophysical properties of lycopene organized in Langmuir-Blodgett films Formation of aggregates. J. Photochem. Photobiol A 107 201-205. 

Bulk NLO studies on luminescent /uc- ReI(CO)3(a-diimine) + complexes by Yam and co-workers note SHG from surfactant derivatives such as (54) and (55) deposited in Langmuir-Blodgett (LB) thin films.110-112 For example, the 532 nm SHG from LB films of the stilbazole derivative (55) is ca. 50% more intense than that from films of the structurally related purely organic salt traiw-.lV-methyl-4-[2-(4-octadecyloxyphenyl)ethenyl]pyridinium iodide.112... 

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