AFRL Nanoscience Technologies: Applications, Transitions and Innovations

摘要

Nanoscience is the study of materials at length scales smaller than those where conventional physics apply and larger than those where atomic physics dominate. It combines contributions from many scientific disciplines, including biology, chemistry, physics, optics, engineering, computer sciences, and mathematics. Nanotechnology is the application of nanoscience by the practical formation of nanoscale structures and integrating them into materials, devices and products. There is no single length scale that defines nanoscience and nanotechnology, but it typically ranges from several tenths of a nanometer to several hundred nanometers. Why are the properties of materials so different at these length scales. The reasons can be as simple as the fact that more and more atoms are close to defects like a surface or internal interface as the size approaches nanometer dimensions. These defects have properties that are very different from the bulk, and a high surface-to-volume ratio is responsible for many useful effects, including highly reactive munitions and fuels and ultra-sensitive chemical and biological sensors. On the other hand, the reasons for the unique properties of nanomaterials can be as complicated as the quantum confinement of electrons into different energy states that give new solid state lasers and infrared detectors. These length scales apply to the size of nano- particles that can be discrete or embedded in conventional materials. They can also apply to the thickness of individual or multiple layers in engineered laminates. The size and spacing of pores and internal interfaces give new properties when arrayed at nanometer length scales. And engineered materials and devices have been produced from amazing combinations of pillars, platelets, tubes, rods and molecules with nanometer dimensions. These features can interact with light and other electromagnetic energy; they can interact with magnetic domains for improved superconductivity; they strengthen metals.