Nanotechnology Lect.5

Self-assembled
Nanoscience will impact the design and fabrication of new materials with innovative properties and functions. Contributions to this field are very widespread, and include enhancing the properties of plastics, ceramics, coatings, composites, fibres and many more. Nanoscience also introduces an entirely new concept in material design, the bottom-up approach of material self-assembly, which is directly inspired from how organic and inorganic materials are created in nature. As a matter of fact, as shown in the first section, nature is a great source of inspiration to materials engineers, since many natural nanomaterials perform extraordinary functions as a result of their inner nanostructure.
The question: What is a?nanostructured material‘? must be considered before discussing examples of various functional nanomaterials. Nanostructured materials are solids or semi-solids (e.g. hydrogels, liquid crystals) characterised by a nano-sized inner structure. They vary differ from crystalline, microstructured and amorphous solids because of the scale order. In crystalline solids, the atoms are neatly arranged in a grid where the distance between neighbouring atoms is well defined, and this order extends to macroscopic dimensions. In contrast, microstructured materials show structural variation only on a micron scale, whereas amorphous materials exhibit short-range order only. In nanostructured materials, the spatial order is at the nanoscale, which lies between the microscopic and the atomic scale.
They can exhibit properties that are drastically different from those of conventional materials, and this is often a direct consequence of the large fraction of grain