chapter  1
22 Pages

Monolayers And Multilayers

Ultrathin and thin films with carefully designed structures and properties have attracted a great deal of interest in recent years [1-5] due to their potential applications in a number of different fields, such as sensors [6-8], detectors [1-3], surface coating [4,5], optical signal processing [9-11], digital optical switching devices [12-14], molecular electronic devices [15-21], nonlinear optics and models mimicking biological membranes [22-24]. These applications require, in general, well ordered films consisting of molecules with specific properties, carefully aligned with respect to each other and to the substrates, and possessing high degree of stability to thermal and chemical changes. Langmuir-Blodgett (LB) technique is a simple but powerful tool for creating carefully controlled supramolecular structures of organized molecular assemblies. The structure, morphology, configuration and various other physical properties of the films obtained by LB technique can be easily modified to suit any specific application. The possibility to synthesize organic molecules almost without limitations and with desired structure and functionality, in conjunction with Langmuir-Blodgett film deposition technique, enables the production of electrically, optically, and biologically active components on

a nanometer scale. It is thus extremely important to get an idea about the relation between the molecular structure and the domain structure on one hand and the various physical properties of such systems on the other. The basic physics involved in such interrelations, as we shall see in this book, is a topic of fundamental importance.