LANGMUIR MONOLAYERS OF TWO-HEADED SURFACTANTS CONTAINING THE UROCANIC ACID MOIETY

The properties of Langmuir layers made up of three bola-ampbiphiles 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 amphiphile (UAC₁₂) were investigated. The area per molecule at the air-water interface was measured. Moreover, a modeling study was performed to visualize the conformation of these compounds at the air / water interface. The pressure-area isotherm and the molecular modeling study indicate that a folded conformation is possible only for the UAC₁₆UA bola-amphiphile. This result could be connected to the ability of UAC₁₆UA to form micelles.