Self- Assembly and Nanostructured Materials

"Nanostructured materials " are those having properties defined by features smaller than 100 nm. This class of materials is interesting for the reasons: i) They include most materi-als, since a broad range of properties-from fracture strength to electrical conductivity-depend on nanometer-scale features. ii) They may offer new properties: The conductivity and stiffness of buckytubes, and the broad range of fluorescent emission of CdSe quan-tum dots are examples. iii) They can mix classical and quantum behaviors. iv) They offer a bridge between classical and biological branches of materials science. v) They suggest approaches to "materials-by-design". Nanomaterials can, in principle, be made using both top-down and bottom-up techniques. Self-assembly bridges these two tech-niques and allows materials to be designed with hierarchical order and complexity that mimics those seen in biological systems. Self-assembly of nanostructured materials holds promise as a low-cost, high-yield technique with a wide range of scientific and technological applications. 9.1.1. Materials Materials are what the world is made of. They are hugely important, and hugely in-teresting. They are also intrinsically complicated. Materials comprise, in general, large numbers of atoms, and have properties determined by complex, heterogeneous structures. Historically, the heterogeneity of materials-regions of different structure, composition