Langmuir transfer

This Blodgett-Langmuir transfer is almost instantaneous (30). 

Langmuir [ 146] gave an instructive interpretation to this rule. The work W to transfer one mole of solute from bulk solution to surface solution should be... 

Electron diffraction studies are usually limited to transferred films (see Chapter XV), One study on Langmuir films of fatty acids has used cryoelectron microscopy to fix the structures on vitrified water [179], Electron diffraction from these layers showed highly twinned structures in the form of faceted crystals. 

The transfer of Langmuir films from the air-liquid surface to a solid substrate has come to be known as Langmuir-Blodgett deposition, after its developers [130, 131]. The solid substrates are usually hydrophilic surfaces such as... 

Figure C2.4.2. Schematic sideview of tlie trough. The movable barrier is used to push tire molecules on tire subphase togetlier in tire Langmuir film which is subsequently transferred to a solid substrate.

Riohard J, Barruad A, Vandevyver M and Ruaudel-Teixier A 1988 A 2-step transfer of oonduoting Langmuir films from a glyoerol subphase Thin Solid Films 159 207-14... 

Saint Pierre M and Dupeyrat M 1983 Measurement and meaning of the transfer prooess energy in the building up of Langmuir-Blodgett multilayers Thin Solid Films 99 205-13... 

The treatment here is restricted to the Langmuir or constant separation factor isotherm, single-component adsorption, dilute systems, isothermal behavior, and mass-transfer resistances acting alone. References to extensions are given below. Different isotherms have been considered, and the theory is well understood for general isotherms. 

One of the new trends in chemical analysis appeared in the last decade is that the miniaturization. It becomes apparent in the miniaturization of analytical devices, separation procedures, measuring tools, analyzing samples and as a consequent the term micro have appeared. Further development of this trend have led to transfer from the term micro to nano one (nanoparticles, nanofluides, nanoprobes, nanoelectrodes, nanotubes, nanoscale, nanobarcode, nanoelectrospray, nanoreactors, etc). Thereupon a nanoscale films produced by Langmuir-Blodgett (LB) technique are proposed for modifying of chemical sensors. 

Stricktly speaking the partial charge transfer parameter Xj which appears in the modified electrochemical Langmuir isotherm (6.36) or (6.41) is not a constant but may vary with 0j or IT. This because, in view of Eq. (6.31) Xj is given by ... 

The second way of preparing L-B monolayer structures, the horizontal lifting method, was introduced by Langmuir and Schaefer. In this method, a compressed monolayer first is formed at the water-air interface, and a flat substrate is then placed horizontally on the monolayer film. When the substrate is lifted and separated from the water surface, the monolayer is transferred onto the substrate, as depicted in Fig. 15(d). 

FIG. 2 Common modes of Langmuir-Blodgett film transfer X-type, Y-type, and Z-type. 

X-ray diffraction has been applied to spread monolayers as reviewed by Dutta [67] and Als-Nielsen et al. [68], The structure of heneicosanoic acid on Cu and Ca containing subphases as a function of pH has been reported [69], as well as a detailed study of the ordered phases of behenic acid [70], along with many other smdies. Langmuir-Blod-gett films have also been studied by x-ray diffraction. Some recent studies include LB film structure just after transfer [71], variations in the structure of cadmium stearate LB films with temperature [72], and characterization of the structure of cadmium arachidate LB films [73], X-ray [74,75] and neutron reflectivity [76,77] data on LB films can be used to model the density profile normal to the interface and to obtain values of layer thickness and roughness. 

Generation of nanoparticles under Langmuir monolayers and within LB films arose from earlier efforts to form nanoparticles within reverse micelles, microemulsions, and vesicles [89]. Semiconductor nanoparticles formed in surfactant media have been explored as photocatalytic systems [90]. One motivation for placing nanoparticles within the organic matrix of a LB film is to construct a superlattice of nanoparticles such that the optical properties of the nanoparticles associated with quantum confinement are preserved. If mono-layers of capped nanoparticles are transferred, a nanoparticle superlattice can be con-... 

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