(82a) Nano-Structured Amphiphile Self-Assembly Phases and Particles: New Urea Surfactants as a Case Study (Invited Talk)

Amphiphiles (including surfactants, lipids and block co-polymers) can self-assemble into a large variety of nano-, micro- and macro-structures that are physically, not chemically, associated. In biological processes, amphiphiles continuously transform from one structure to another. In conjunction with proteins they form the super-assemblies which mediate and control life processes. The ?bottom-up? approach in nanotechnology also requires us to be able to manipulate amphiphile self-assembly. It is generally recognized that both local and global constraints govern the self-assembly behaviour of amphiphiles in solution. This presentation, will include an overview of the molecular, colloidal and interfacial components of these constraints, and include a discussion of how we can use our evolving understanding of these constraints to create new nano-structured self-assembly materials. In particular we will present urea in a new role. We will report the discovery that the strong intermolecular hydrogen bonding of urea can be ameliorated, through select structural modifications to hydrocarbon chain substituents, resulting in surfactant self-assembly and the formation of lyotropic liquid crystalline phases that are thermodynamically stable in excess water. The nano-structured bulk phase can be dispersed in water to form colloidal particles (?colloidosomes?), and both the bulk and dispersed phase are potential new controlled/sustained release and structure-templating materials.