Soap and sand: construction tools for nanotechnology

Nanotechnology is the science of making and using very small structures. As the scales of the constructions become smaller, the existing methods of making these structures--lithography, etching and micromoulding--although constantly improving, will reach physical limits. To overcome the limitations and create smaller, designed and ordered structures, a so-called 'bottom-up' approach must be used. In bottom-up manufacture, self-assembly and nanocasting using molecular assemblies is a burgeoning area of research producing promising materials with current and future applications. In particular, the use of amphiphilic molecules, such as surfactants, which are familiar to most people as the soap bubbles in their kitchen sink, form a range of very uniform structures in the 1-100 nm size range that can be used to direct the structure of other materials. This paper reviews the use of surfactant templating to create nanoscale structures focusing on recent advances in the understanding of how the ordered nanostructures form, and the developing appreciation of how emergent larger-scale structures made of these materials come about.