Langmuir monolayers of two-headed surfactants containing the urocanic acidmoiety

The properties of Langmuir layers made up of three bola-amphiphiles having the general structure UA-C-n-UA, where UA denotes urocanic acid and C-n is an alkyl chain of varying length (n = 8, 12 and 16) and of a monopolar amph iphile (UAC(12)) were investigated. The area per molecule at the air-water interface was measured. Moreover, a modeling study was performed to visuali ze the conformation of these compounds at the air / water interface. The pr essure-area isotherm and the molecular modeling study indicate that a folde d conformation is possible only for the UAC(16)UA bola-amphiphile. This res ult could be connected to the ability of UAC(16)UA to form micelles.