What is Nano?

In its simplest form, nanotechnology concerns itself with the intentional production or manipulation of objects that measure between one and one hundred nanometers in at least one dimension. A nanometer is one billionth of a meter. A human hair is about ten thousand nanometers wide. Broadly speaking, nanotechnology deals with things that are larger than atoms and smaller than cells. The word nanotechnology covers hard metallic and ceramic particles; soft, polymeric molecules; nanoscale features etched into electronic and mechanical substrates; even bulk materials with nanoscale voids, called nanoporous materials.

As a practice, nanotechnology has been around for hundreds of years. Medieval glassmakers used gold nanoparticles to make the ruby red color in stained glass. As a science, it is barely fifty years old. In 1959, Professor Richard Feynman delivered a lecture called “There’s Plenty of Room at the Bottom”, in which he predicted the advent of advanced microscopes and other instruments that would allow the precise positioning of atoms and molecules to enable molecular, or “bottom up” manufacturing. Thirty years later, in 1989, an IBM scientist named Don Eigler spelled out his employer’s initials by using a scanning tunneling microscope to position thirty five-xenon atoms on a nickel substrate. Nanotechnology is the manifestation of Dr. Feynman’s dream come true.

Simultaneous with the development of advanced microscopes and other detection devices, over the past several decades advancements in computer technology have facilitated increasingly precise process sensing and controls instrumentation, which in turn, has facilitated the production of materials at particle sizes and molecular configurations that only rarely occur in nature.

Because nanomaterials exist at the boundary of the bulk regime, which is governed by the laws of classical mechanics, and the atomic regime, which is governed by theories of quantum physics, nanomaterials tend to behave differently than their everyday bulk counterparts. Most significant among these differences are those associated with increased surface area resultant of smaller particle size. Because chemical reactions take place on surfaces, as opposed to within the internal mass of an object, nano-particles have more external surface area on which chemical reactions may take place. Although research is ongoing, we know that some nanoscale materials exhibit different physical, chemical, reactive, morphological, optical, conductive, thermal and catalytic characteristics than they do at bulk scale. These differences affect many of the physical and chemical characteristics of various elements in different ways. For instance, gold nano-particles melt at a lower temperature than their bulk scale counterparts. Carbon nano-tubes are made of the same atoms as pencil lead, but due to their nano-structure, are stronger than steel. Some novel nanoscale materials, called metamaterials, refract light exactly opposite the way they would be expected to under the conventional laws of optics.

The exploitation of these novel characteristics promises to yield incremental improvements to many conventional materials in the near term and to enable the development of revolutionary products in the future. We have been all been using sunscreen with titanium dioxide nano-particles for years. The steel industry has been making steel tougher by the addition of titanium and niobium nano-crystals since the 1960s. Environmental remediation companies are using zero-valence nanoscale iron particles to mineralize subsurface halide contaminants. The glass industry is applying nanoscale coatings on windows to make them self-cleaning. Bandages impregnated with silver nano-particles serve as long-lasting germicides. Over the next several decades nanotechnology is likely to influence virtually every aspect of human endeavor from energy and infrastructure to communications and health care.