Nanoengineering materials and their properties

Nanoengineering Materials

Nanotechnology is the ability to precisely control matter at the atomic and molecular level to make new and better materials, products, and devices. While the technology remains in a state of evolution, nanotechnology has the potential to revolutionize the fields of medicine, drug delivery systems pharmaceuticals, biotechnology, energy, environmental remediation, and much more. The ability to manipulate materials at the atomic and molecular level will allow scientists to identify yet unknown applications for these processes at the nanoscale, thereby providing the ability to control the fundamental properties of materials that have remained unchanged throughout the history of mankind. These emerging nanotechnologies will also provide scientists with the ability to improve the efficiency of chemical reactions, develop harder and more durable materials, manufacture drugs with precision activity, and create diagnostic tools that actually can be placed inside cells, as well as realizing numerous other accomplishments that remain unimaginable today. This paper provides a review of the relevant peer-reviewed and scholarly literature to determine what nanoengineering is, and what advantages and disadvantages are associated with the emerging technology. A discussion of current and future trends is followed by a summary of the research and salient findings in the conclusion.

Nanoengineering Materials: Engineering and Applications

The history of mankind has been marked by several technological ages during which the ways materials have been used have changed in substantive ways. Despite these world-changing technological innovations, though, the basic materials used in manufacture of goods and products have remained substantially the same. Things are changing today, though, and the materials used in some manufacturing applications are taking place at the atomic level, where scientists are able to manipulate individual atoms in a process known as nanoengineering. This paper provides a review of the relevant peer-reviewed and scholarly literature to report upon the developments that have been created in nanotechnology to date. A review of material content and an analysis of the advantages and/or disadvantages of the materials used is followed by a discussion concerning the purpose and application of these materials, and why these new developments represent a revolutionary concept for engineering materials. A summary of the research will be presented in the conclusion.

Review and Discussion

Background and Overview.

At the turn of the 21st century, the U.S. president's proposed National Nanotechnology Initiative proclaimed that "the emerging fields of nanoscience and nanoengineering are leading to unprecedented understanding and control over the fundamental building blocks of all physical things. These developments are likely to change the way almost everything -- from vaccines to computers to automobile tires to objects not yet imagined -- is designed and made" (quoted in Anton, Silberglitt & Schneider, 2001 at p. 1). In their book, the 21st Century at Work, Karoly and Panis (2004) report that, "New materials made possible by nanotechnology architectures, beyond what is possible with chemistry alone, may offer improved performance and reliability with applications to a tremendous array of products. Manufacturing methods developed through nanoscience and nanoengineering are expected to evolve to the nanometer scale, with the ability to precisely control nanoscale building blocks that are then assembled into larger structures" (p. 98). As a recent example, these authors cite the creation of a new designer material, self-assembled in three dimensions from two different types of particles in increments of less than 1 nanometer. "The custom properties of the new material reflect those of the original components" (Karoly & Panis, 2004, p. 99).

According to Deal (2002), the term "nano" is from the Greek word for "dwarf"; when used as a prefix for any unit of measure, the term means a billionth of that unit. Therefore, a nanometer is one-billionth of a meter. The term "nanotechnology" refers to the manipulation or self-assembly of individual atoms, molecules, or molecular clusters into structures with dimensions in the 1-to 100-nanometer range to create materials and devices with new or fundamentally different properties (Deal, 2002). In his study, "Nanotechnology and Nanoengineering," Suk (2001) defines nanotechnology as "the creation of functional materials, devices, and systems through the control of matter at a scale of 1-100 nanometers, as well as the exploitation of novel properties and phenomena developed at that scale" (p. 37).

While the term "nanotechnology" is recent in origin, the fundamental processes involved are not. According to Suk, "Photography and catalysis are examples of nanotechnology that were developed through the process of trial and error and that have been around for a while. Nature is the master of nanotechnology, transforming atoms of various elements into miniature building blocks and power plants that result in a living, functional person" (2001, p. 37). Likewise, the photosynthetic processes that transform the sun's energy into chemical energy in plants represent another good example of nature's own nanotechnology in action (Suk, 2001).

Advantages of Nanotechnology.

While the fundamental processes involved in nanotechnology may be as old as the universe itself, the manner in which the materials that are used in these processes has changed in fundamental ways in recent years. According to Deal (2002), each of the technological ages throughout mankind's history (i.e., Stone Age, Iron Age, and the Industrial Revolution) has been characterized by technological milestones that reflect significant changes in the way materials and technology were used at the time. Today, Deal notes that, "As we moved into the Space and Information ages, materials and process technologies introduced new manufacturing methods, the transistor and microchip, and the digital computer. We see many inventions and innovations in engineering and chemistry. This is the age where we see the introduction of plastics, polymers, semiconductors, and space travel" (p. 21).

In spite of these advances and innovations in technology, the manner in which various products and goods are manufactured remains at the "material level." As Deal points out, "Raw materials are shaped and formed using heat and pressure or machined using chip removal processes. However, nanotechnology, nanoscience, and nanoengineering focus on the design and manipulation of individual atoms to produce tailor-made products and devices" (p. 22). In this regard, researchers now possess the ability to manipulate and combine materials at the atomic level, a process that this authority and others believe will revolutionize the production of virtually every human-made object and fuel a new technology revolution in ways that remain unclear at the present (Deal, 2002). One authority suggests that, "Nanotechnology has given us the tools... To play with the ultimate toy box of nature -- atoms and molecules. Everything is made from it... The possibilities to create things appear limitless" (Stormer, 1999, p. 1). According to Lemley (2005), "The unique behavior of materials at the nanoscale offers intriguing possibilities for the cheap construction of rare molecules, the production of light and incredibly strong microfibers, and the production of ultrasensitive detectors" (p. 601).

Given that the materials involved in nanoengineering applications are identical to the materials used in traditional manufacturing processes, it is reasonable to question what advantages nanotechnology holds for mankind in the future. According to Deal, "All natural materials and systems establish their foundation at the nanoscale. That is to say that the properties of materials are established one atom at a time and in the unique manner in which they are arranged. By controlling matter at the molecular level, scientists and engineers can tailor the fundamental properties of materials precisely as desired" (p. 22).

Therefore, while wood will likely still be wood in the future in many ways, and the current applications such as furniture manufacture and housing construction for which it is typically used will probably be unaffected in substantive ways, other applications will likely be affected by nanoengineering processes in fundamental ways. For example, "By determining material properties at the nano level, nanotechnology has the potential to affect the production of nearly all human-made objects. The implications are far reaching -- from automobiles, tires, fuels, and electronic circuits to advanced medicines and tissue replacements. It is possible to develop new materials not found in nature by manipulating and assembling atoms in a precise manner" (emphasis added) (Deal, 2002, p. 23). Indeed, it is not too far-fetched to imagine that even lowly wood can somehow be transformed at the molecular level to become a much more robust material for furniture manufacture. Chairs that automatically conform to the sitter's posture are conceivable, just as furniture that can change colors depending on the owner's whims at a given point in time.

Likewise, according to a recent report from Uldrich, "A Cautionary Tale: Nanotechnology and the Changing Face of the Electric Utility Industry" (2006), the broadest definition of nanotechnology is the precise control of matter at the atomic and molecular level to make new and better materials, products, and devices. "A practical application of this is demonstrated with a simple example," Uldrich advises. "Consider a lump of coal and a diamond. Both are made from the same material -- carbon atoms -- but how their atoms are arranged differs and matters greatly. One is a common source of energy, while the other is suitable for an engagement ring" (p. 16).

To date, nanotechnology has become sufficiently refined so that several nanotechnology companies have perfected the ability to manipulate carbon atoms and are already creating 2-carat diamonds that are identical to natural diamonds at the molecular level at prices far less than their natural counterparts. From a materials development perspective, this is the important part: "The significance of this advance is this: if a material as expensive and rare as a diamond can be turned into a 'commodity,' then the applications of a variety of other materials, including everything from copper and ceramics to steel, can also be improved and utilized in different ways" (Uldrich, 2006, p. 17). From a pragmatic perspective, these developments mean that the equipment parts and components currently in use in the electric utility industry can be "retrofitted" using nanoengineered materials to make them more efficient and durable. "For instance," Uldrich reports, "high-temperature and sulfur-tolerant nanomaterials can be manufactured to withstand the harsh conditions of coal-fired plants; or nanoscale ceramics coatings can be employed to protect steel, nickel and other metallic components from corrosion. The end benefit is that electric utility providers can improve their operating margins by making existing equipment both last longer and operate at higher levels of efficiency" (p. 17). Therefore, by providing scientists with the ability to create "tailor-made" materials at the atomic and molecular level, nanoengineering techniques hold enormous promise for mankind in the future in ways that remain undetermined as yet. As Senator George Allen has emphasized, though, "The fields of nanoscience, nanoengineering, and nanotechnology have the real potential to transform almost every aspect of our lives and commerce" (2005, p. 55).

Disadvantages Associated with Nanotechnology.

While the advantages of nanoengineering are numerous and new applications continue to be discovered, there are some potential disadvantages associated with these trends that must be taken into account as well. In this regard, although the potential for nanotechnology is enormous, researchers in the field remain cautious about promising "too much, too soon" (National Nanotechnology Initiative, 2003). According to Karoly and Panis, "As with all technologies, considerable lags can occur between basic scientific discoveries and full-scale commercial applications. However, for the 10- to 15-year horizon, nanotechnology is almost certain to generate evolutionary technological change that enhances the capability of existing products and lowers costs" (p. 96).

Concomitantly, many of the innovations in nanotechnology also carry with them significant social, legal, and ethical implications, as well as national security concerns, that need to be addressed as the technologies continue to evolve. According to these authors, "If public acceptance of the new technologies is slow to materialize, their adoption and diffusion may not match the pace of discovery" (Karoly & Panis, 2004, p. 97). Likewise, as Lemley (2005) cautions, "Nanotechnology is at a speculative early stage; only a few nanotech inventions have so far actually made it into commercial products. But the expectations surrounding the field are immense, ranging from a utopia of free energy and abundant materials that will be one of the 'major drivers of economic growth' in the foreseeable future to fears of environmental catastrophe" (p. 602). Finally, as Gulson and Wong (2006) report, "Numerous publications and reports have expressed health and safety concerns about the production and use of nanoparticles, especially in areas of exposure monitoring, personal use, and environmental fate and transport.... By design, many of the nanotechnology products in development or in use contain a metal (or metalloid in the case of arsenic)" (p. 1486).

Current and Future Trends.

Spending on nanotechnology research has reached unprecedented levels in recent years, with a record $9.6 billion being spent in 2005 alone; the respective sources for this funding were as follows:

Table 1.

Sources of Nanotechnology Research Funding in 2005.

Source

Amount

Government funding

4.61 billion

Corporate funding

4.465 billion

Venture capital

508.5 million

Source: The Nanotech Report, 2006.

Figure 1. Sources of Nanotechnology Research Funding in 2005.