Nanotechnology operates at the first level of organization of atoms and molecules for both living and anthropogenic systems. This is where the properties and functions of all systems are defined. Such fundamental control promises a broad and revolutionary technology platform for industry, biomedicine, environmental engineering, safety and security, food, water resources, energy conversion, and countless other areas.
The first definition of nanotechnology to achieve some degree of international acceptance was developed after consultation with experts in over 20 countries in 1987–1898 (Siegel et al., 1999; Roco et al., 2000). However, despite its importance, there is no globally recognized definition. Any nanotechnology definition would include three elements:
1. The size range of the material structures under consideration — the intermediate length scale between a single atom or molecule, and about 100 molecular diameters or about 100 nm. Here
we have the transition from individual to collective behavior of atoms. This length scale condition alone is not sufficient because all natural and manmade systems have a structure at the nanoscale.
2. The ability to measure and restructure matter at the nanoscale; without it we do not have new understanding and a new technology; such ability has been reached only partially so far, but
significant progress was achieved in the last five years.
3. Exploiting properties and functions specific to nanoscale as compared to the macro- or microscales; this is a key motivation for researching nanoscale.
According to the National Science Foundation and NNI, nanotechnology is the ability to understand, control, and manipulate matter at the level of individual atoms and molecules, as well as at the “supramolecular” level involving clusters of molecules (in the range of about 0.1 to 100 nm), in order to create materials, devices, and systems with fundamentally new properties and functions because of their small structure. The definition implies using the same principles and tools to establish a unifying platform for science and engineering at the nanoscale, and employing the atomic and molecular interactions to develop efficient manufacturing methods.
There are at least three reasons for the current interest in nanotechnology. First, the research is helping us fill a major gap in our fundamental knowledge of matter. At the small end of the scale — single atoms and molecules — we already know quite a bit from using tools developed by conventional physics and chemistry. And at the large end, likewise, conventional chemistry, biology, and engineering have taught us about the bulk behavior of materials and systems. Until now, however, we have known much less about the intermediate nanoscale, which is the natural threshold where all living and manmade systems work. The basic properties and functions of material structures and systems are defined here and, even more importantly, can be changed as a function of the organization of matter via ‘‘weak” molecular interactions (such as hydrogen bonds, electrostatic dipole, van der Waals forces, various surface forces, electro-fluidic forces, etc.). The intellectual drive toward smaller dimensions was accelerated by the discovery of size-dependentnovel properties and phenomena. Only since 1981 have we been able to measure the size of a cluster of atoms on a surface (IBM, Zurich), and begun to provide better models for chemistry and biology selforganization and self-assembly. Ten years later, in 1991, we were able to move atoms on surfaces (IBM, Almaden). And after ten more years, in 2002, we assembled molecules by physically positioning the component atoms. Yet, we cannot visualize or model with proper spatial and temporal accuracy a chosen domain of engineering or biological relevance at the nanoscale. We are still at the beginning of this road. A second reason for the interest in nanotechnology is that nanoscale phenomena hold the promise for fundamentally new applications. Possible examples include chemical manufacturing using designed molecular
assemblies, processing of information using photons or electron spin, detection of chemicals or bioagents using only a few molecules, detection and treatment of chronic illnesses by subcellular interventions, regenerating tissue and nerves, enhancing learning and other cognitive processes by understanding the “society” of neurons, and cleaning contaminated soils with designed nanoparticles. Using input from industry and academic experts in the U.S., Asia Pacific countries, and Europe between 1997 and 1999, we have projected that $1 trillion in products incorporating nanotechnology and about 2 million jobs worldwide will be affected by nanotechnology by 2015 (Roco and Bainbridge, 2001). Extrapolating from information technology, where for every worker, another 2.5 jobs are created in related areas, nanotechnology has the potential to create 7 million jobs overall by 2015 in the global market. Indeed, the first generation of nanostructured metals, polymers, and ceramics have already entered the commercial marketplace.