CHEMICAL SENSORS BASED ON LB FILMS

The field of chemical sensors based on LB films is growing very quickly. LB films are very thin and regular, and molecular conformation and orientation can be controlled. LB films can be used to immobilize enzymes by a very mild process which preserves their catalytic activity: this paper reviews bio-sensors based on LB films. It also reviews ion sensors based on LB films and black lipid membranes (BLM), and chemical sensors based on LB films. Special emphasis is given to the unique possibility afforded by the LB method of tailoring molecular assemblies designed for a specific property. An example is given of a phosphine sensor based on a cleverly designed molecular assembly which provides both high sensitivity and easy transduction. The problem of defects in LB films is discussed and remains one of the major problems of LB sensors since it governs the response time. During the last three or four years, a marked increase in interest in the field of chemical and bio-sensors has been observed. This is, of course, because industry and pollution require more and more sophisticated sensors. But this is also because efficient methods of building up molecular edifices exhibiting specific properties are now emerging: the Langmuir-Blodgett (LB) method is one of the most efficient, though quite simple.