Langmuir monolayers are formed by spreading an amphiphilic molecule at the air-water interface and its interface properties are studied upon compression of the monolayer. The main requirement of the molecule is that the solvent in which is dissolved in should be immiscible with water and fairly volatile. This requirement must be fulfilled such that the solvent could evaporate within 10-15 min and the monolayer would be formed only by the amphiphilic molecules. Compression can be applied to the monolayer and a change in the surface pressure as function of the molecular area can be followed. Compression is a very convenient method to control the packing of a monolayer or in other words the intermolecular distance. This aspect is important because arrays of quantum dots (QDs) can be formed by various techniques, e.g. lithographic methods and upon deposition on metallic substrates new electronic properties given by the array could arise.