Langmuir-Blodgett method

The observation that Langmuir monolayers often exist as phase-separated domains has begun to be exploited as a means to produce LB monolayers with two-dimensional patterns. This approach aims to form, transfer, and stabilize these domains on appropriate substrates by combining the Langmuir-Blodgett method with the covalent bonding aspect of self-assembly. There are a small number of studies, and the possible further functionalization of the domains and use of different combinations of materials make this area promising for the construction of patterned films. 

A. Battaud, H. Perrot, V. Billard, C. Martelet, and J. Therasse, Study of immunoglobulin G thin layers obtained by die Langmuir-Blodgett method application to immunosensors. Biosens. Bioelectron. 8, 39—48 (1993). 

The Langmuir-Blodgett method has been used to prepare hybrid films of an anionic Ru(ll) cyanide polypyridyl complex with LDHs [170]. An LDH film was formed on mica owing to the interaction between LDHs particles and the Ru(ll) cyanide polypyridyl complex that was pre-dispersed on the surface of mica. Water-in-oU emulsions composed of octane, water and sodium dodecyl sulfate (SDS) have been used to synthesize Mg/Al LDHs with carbonate as the interlayer anion [171] by constant pH or variable pH methods. A floccule or fiber-like LDH material that possesses similar chemical composition and properties to that synthesized using a conventional variable pH method was obtained. The resulting LDH shows high surface area and a narrow distribution of mesopores. 

Figure 5.25 — Flow-through ion-selective optrode based on a multilayer lipidic membrane prepared by the Langmuir-Blodgett method. (A) Cross-sectional view of the composite six-layer membrane (four layers of arachidic acid/ valinomycin covered by an arachidic acid and rhodamine dye bilayer). (B) Optical arrangement integrated with the sensor, which is connected to a flow system. LS light source Ml and M2 excitation and emission monochromator, respectively FI and F2 primary filters M mirror LB lipid-sensitive membrane in a glass platelet FC flow-cell A amplifier D display P peristaltic pump. (Reproduced from [107] with permission of the Royal Society of Chemistry).

Arden and Fromherz [51-53] have reported elegant work involving mono-layers of surfactants transferred to electrodes by the Langmuir-Blodgett method. Some results are shown in Figure 28.10. Two separate cationic dyes, thiacyanine (A) and oxacyanine (D), were synthesized with C18 alkyl chains, so that they would form oriented monolayers on water-air interfaces. By standard techniques, these were transferred alternatively or in sequence to n-ln203 electrodes, as... 

Improvements in the membranes have also been made according to the purpose of measurements, e.g., by adopting the Langmuir-Blodgett method [29] or the monolayer of thiol-containing lipids [30]. 

SLBs can be formed by either Langmuir Blodgett methods or through the fusion of small unilamellar vesicles to aplanar solid substrate.2,8 Either way it is relatively straightforward to incorporate ligands into these membrane models. Indeed, any numbers of species including... 

Electron Microscopy. A modified Langmuir-Blodgett method was used to transfer monolayer samples to electron microscope screens that were sandwiched between Formvar and a glass plate (5, 6). A motor drive raised the plate slowly through the water-air interface, and a variable-speed motor drive moved the compressing barrier at a rate that maintained constant surface pressure during the transfer. Many samples were transferred at low surface pressures because the lipids in membranes are undoubtedly subjected to relatively small horizontal or surface pressures. 

Coating Mono- and Multilayers on Solid Substrates Langmuir-Blodgett Method... 

Illustration showing the Langmuir-Blodgett method [54] of depositing organic films D = dipping, L = lifting... 

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