Sensors, Langmuir-Blodgett films

Choi J.W., Bae J.Y., Min J., Cho K.S., Lee W.H., Fiber-optic ethanol sensor using alcohol dehydrogenase-immobilized Langmuir-Blodgett film, Sensor Mater. 1996 8 493-504. 

Figure 130. Langmuir-Blodgett film sensor response at varying NHj concentrations. Reprinted with permission from Nappa, M. Valentine,. S. /. Am. Chem. Soc. 1978, 100, 5075. 1978 American Chemical Society.

NANOSCALE LANGMUIR-BLODGETT FILMS AS SENSITIVE LAYERS OF CHEMICAL SENSORS... 

The results illustrated above show that the CFT method is suitable for making chemical-sensor measurements using both bulk polymers and, in particular, thin film materials that are intrinsically weak conductors. Therefore, the CFT looks premising for such materials as poly(phenylacetylene) derivatives 24., for which carefully shielded electrometer measurements have been required in the past because of current levels at the threshold of detectability. Furthermore, the fact that the CFT always makes AC measurements reduces the problem of DC polarization of electrodes. In addition, the CFT approach should be suitable for other "chemiresistor" applications, such as the metal-substituted phthalocyanines proposed by Jarvis et. al. 2 and for Langmuir—Blodgett films 26. which, because they are so thin, may prove impossible to use in parallel-plate form, but which can be routinely used with the high-sensitivity interdigi-tated-electrode approach provided by the CFT. 

Kusano, H. Kimura Shin, L Kitagawa, M. Kobayashi, H. Application of Cellulose Langmuir-Blodgett Films as Humidity Sensors, and Characteristics of the Sorption of Water Molecules into Polymer Monolayers. Thin Solid Films 1997, 295, 53-59. 

Because of their electrical, optical, and redox properties as well as the thermal and chemical stability, the Pcs also have been tried in the detection of volatile organic compounds and poisonous gases, which is very important for environment and human health. In the past decades, the possible applications of Pc thin film as sensor for atmospheric gaseous pollutants have been extensively studied [73, 74], Langmuir-Blodgett films of some multinuclear and multidouble-decker lutetium Pcs have also been used for those measurements [75,76], More details about conductivity and sensing properties of Pcs can be found elsewhere [77,78]. 

Fig. 4.34. Typical response of a LuPc2 Langmuir-Blodgett film expressed as the fractional change in resistance (AR/R) x 100 towards (a) refined olive oil (b) lampante olive oil (c) extra virgin olive oil and (d) ordinary olive oil. Reproduced with permission from N. Gutierrez et al., Sensors and Actuators B 77,437, 2001.

Okahata, Y, Tsuruta, T., Ijiro, K., and Ariga, K., Langmuir-Blodgett films of an enzyme-lipid complex for sensor membranes, Langmuir, 4, 1373-1375, 1998. 

Wong, H. E., Langmuir-Blodgett Film Technology in the Development of Selective Chemical Sensors, Ph. D. Thesis, University of Toronto, 1987. 

Valli L., Phthalocyanine-based Langmuir-Blodgett films as chemical sensors, Adv. Colloid Interface ScL, 116(1-3), 13-44, 2005. 

Gutierrez N., Rodriguez-Mendez M. L., and de Saja J. A., Array of sensors based on lanthanide bisphtahlocyanine Langmuir-Blodgett films for the detection of olive oil aroma, Sens. Actuators B, 77, 437-442, 2001. 

Valkova L., Borovkov N., Maccioni E., Risani M., Rustichelli R, Erokhin V., Rattemolli C., and Nicolini C., Influence of molecular and supramolecular factors on sensor properties of Langmuir-Blodgett films of tert-butl-substituted copper azaporphyrines towards hydrocarbons. Colloids. Surf. A., 198-200, 891-896, 2002. 

Rodriguez-Mendez M. L., Langmuir-Blodgett films of rare-earth lanthanide bisphthalo-cyanines. Applications as sensors of gases and volatile organic compounds. Comments. Inorg. Chem., 22, 227-239, 2000. 

Great attention has been paid to the construction of Langmuir-Blodgett films to be used in various sensors, e.g. metals, bound to imidazole- [97], azobenzene-containing [98], polyaniline [99] and other films. 

Riul, A., et al. 2002. Artificial taste sensor Efficient combination of sensors made from langmuir— blodgett films of conducting polymers and a ruthenium complex and self-assembled films of an azobenzene-containing polymer. Langmuir 18 239. 

Alessio, P., Pavinatto, F.J., Oliveira Junior, O.N., Saez, J.A.S., Constantino, C.J.L., Rodr(guez-M6ndez, M.L. Detection of catechol using mixed Langmuir-Blodgett films of a phospholipid and phthalocyanines as voltammetric sensors. Analyst 135, 2591-1599 (2010). doi 10.1039/c0an00159g... 

Pal, R Nandi, D. Misra, T. N. Immobilization of alcohol dehydrogenase enzyme in a Langmuir-Blodgett film of stearic acid its application as an ethanol sensor. Thin Solid Films 1994,1, 138-143. 

The novel functionalized polythiophenes, poly[3-(6-hydroxyhexyl)thiophene] and poly(3-octanethio-2,2 -bithiophene), have been used as selective coating materials for quartz crystal microbalance (QCM) sensors. These Langmuir-Blodgett film coated QCM sensors are useful in detecting heavy metal ions in aqueous solution, which are major pollutants in wastewater (54). 

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