Nanostructured self-assembly materials formed by non-ionic urea amphiphiles

Urea is an extremely versatile molecule that has been widely used for many years in a diverse range of applications. The physicochemical properties of urea have been well studied with respect to the role of hydrogen bonding in biological and chemical systems. Urea-based amphiphiles, in contrast, have received little attention with respect to physicochemical properties. Studies reported in the last few years have demonstrated that specific urea amphiphiles display interesting lyotropic liquid crystalline phase behaviour. These nanostructured self-assembly phases are potential candidates for a number of novel applications. In this work, we review the physicochemical properties of non-ionic urea-based amphiphiles, including those of the solid state, insoluble monolayers residing at the air-water interface, Langmuir-Blodgett films deposited on solid substrates and lyotropic liquid crystalline phases. In addition, we present new data that extends the characterisation of the solid state and lyotropic properties of isoprenoid branched urea surfactants.