Characterization of Langmuir-Blodgett films

Y. Hirata, M.-L. Laukkanen, K. Keinanen, H. Shigematsu, M. Aizawa, and F. Mizutani, Microscopic characterization of Langmuir-Blodgett films incorporating biosynthetically lipid-tagged antibody. Sens. Actuators B 76, 181-186 (2001). 

In situ Characterization of Langmuir-Blodgett Films by using a Quartz Crystal Microbalance as a... 

The application of FT-IR to a wide variety of interfacial phenomena is possible using either attenuated total reflectance (ATR) or grazing angle reflection -absorption. The details of these optical techniques are discussed in a subsequent chapter, in the context of characterization of Langmuir - Blodgett films and self-assembled mono and multilayers. However, ATR has been applied in a number of other areas which will be mentioned here. 

K. Ariga, Y. Okahata, In Situ Characterization of Langmuir-Blodgett Films diu-ing a Transfer Process. Evaluation of Transfer Ratio and Water Incorporation by Using a Quartz Crystal Microbalance , Langmuir, 10, 3255 (1994)... 

Luk S Y, Mayers F R and Williams J O 1988 Preparation and characterization of Langmuir-Blodgett films of mesoporphyrin-IX dimethylester indium chloride Thin Solid Films 157 69-79... 

The technique of infrared reflection absorption spectroscopy (IRAS) was first described both theoretically and experimentally in the late fifties by Francis and Ellison [10]. They used the technique for structural characterization of Langmuir Blodgett films of metal stearates on highly reflecting metal substrates. It is worth noting that IRAS is sometimes called IRRAS or RAIRS. The technique is briefly described in the following, a detailed theoretical treatment can be found elsewhere [10, 11]. 

We review useful usages of a quartz crystal-microbalnce (QCM) as tool of in situ characterization of Langmuir-Blodgett (LB) films transfer ratio and water incorporation during a transfer process, swelling behavior in water subphase, and detachment at the air-water interface. 

Hagenhoft B., Benninghoven, A., Siegmund, H.-U., Holtkamp, D. (1992) Characterization of Langmuir-Blodgett overlayers by time-of-flight secondary ion mass spectrometry. Thin Solid Films, 210/211, 601-605. 

L. Robitaille and M. Leclerc, Synthesis, characterization and Langmuir-Blodgett films of fluorinated polythiophenes, Macromolecules 27 IS47 (1994). 

Transmission electron microscopy (TEM) can resolve features down to about 1 nm and allows the use of electron diffraction to characterize the structure. Since electrons must pass through the sample however, the technique is limited to thin films. One cryoelectron microscopic study of fatty-acid Langmuir films on vitrified water [13] showed faceted crystals. The application of TEM to Langmuir-Blodgett films is discussed in Chapter XV. 

The area of colloids, surfactants, and fluid interfaces is large in scope. It encompasses all fluid-fluid and fluid-solid systems in which interfacial properties play a dominant role in determining the behavior of the overall system. Such systems are often characterized by large surface-to-volume ratios (e.g., thin films, sols, and foams) and by the formation of macroscopic assembhes of molecules (e.g., colloids, micelles, vesicles, and Langmuir-Blodgett films). The peculiar properties of the interfaces in such media give rise to these otherwise unlikely (and often inherently unstable) structures. 

D.K. Schwairtz, Langmuir-Blodgett Film Structure, Surf. Set Reports 27 (1997) 245-334. (Review on structural and thermod5mamlc properties of LB films brief description of characterization techniques.)... 

Richardson, T., Roberts, G.G., Polywka, M.E.C., Davies, S.G. Preparation and characterization of organotransition metal Langmuir-Blodgett films. Thin Solid Eilms 160, 231-239 (1988)... 

Due to the surface sensitivity surface enhanced fluorescence has become particularly popular in the characterisation of thin molecular films, such as Langmuir-Blodgett films and self-assembled biomembranes. Two surface enhanced spectroscopic techniques (surface enhanced IR absorption, SEIRA, and surface enhanced fluorescence, SEF) were recently applied to the study of biomembrane systems by the group of Reiner Salzer [323]. With SEIRA, specific fingerprints of biomolecules could be obtained with a tenfold IR intensity enhancement With SEF signal enhancement factors greater than 100 were obtained. The enhancement factor was very dependent on the properties and structure of the metal clusters used. With the two techniques biomembranes formed from vesicles with embedded nicotinic acetylchoHne receptors were spectroscopically characterized. 

Mattoso L. H. C., Mello S. V., Riul A Jn, Oliverira 0. N. Jn, and Faria R. M., nthesis and characterization of poly[o-phenetidineJ for the lubrication of Langmuir and Langmuir-Blodgett films. Thin Solid Films, 1994,244,714-717. 

Kim, J.H., et al. 1995. Preparation and characterization of poly(p-phenylene vinylene) Langmuir-Blodgett film formed via precursor method. Synth Met 71 2023. 

SEIRA and SERS are powerful techniques for stmctural characterization of ultra thin films and well-ordered monolayer on metal surfaces. Thin films at interfaces are prepared by different procedures and developed for various applications. The fabrication and characterization of ultra thin films is a permanent area of research where some of the most interesting subjects are (a) bilayers and monolayers at liquid-liquid interface, (b) adsorption monolayers and Langmuir (water-insoluble) monolayers at air-water interface, (c) adsorption films and self-assembled monolayers (SAMs) at liquid-solid interface and Langmuir-Blodgett Alms, cast (deposit) films and spin-coat films at air-solid interface. Studies about molecular organization of monolayers of porphyrins derivatives, of azamacrocy-cles and their metallic derivatives among the many SEIRA applications to films and interfaces, were published . 

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