In the 1980s, K. Eric Drexler popularized the term “nanotechnology,” proposing machines the size of molecules and computers smaller than cells. Today, nanotechnology is used in a variety of fields and has new physical properties related to quantum mechanics. While nanotechnology has revolutionized materials science, it has also been studied for its potential harms.
When K. Eric Drexler first popularized the word “nanotechnology” in the 1980s, he proposed ideas for machines the size of molecules, motors a few nanometers wide, robotic arms, and even entire computers much smaller than a cell. Drexler spent the next decade describing and analyzing these amazing devices and responding to accusations that his work was science fiction. As nanotechnology became a widely accepted concept, the meaning of the word shifted to refer to simpler technologies on the nanometer scale.
Most of today’s use of the word “nanotechnology” was first proposed by Drexler. Traditionally, nanotechnology meant making things from the bottom up with atomic-level precision, a theoretical ability envisioned as early as 1959 by renowned physicist Richard Feynman, winner of the Nobel Prize in Physics. “I want to build a billion little factories, models of each other, all manufacturing at the same time… As far as I can see, the principles of physics are not opposed to the possibility of manipulating things at the atomic scale – it’s not an attempt to break any laws, it’s something that in principle we can do, but in practice we haven’t done it because we’re too big.”
The word “nano” itself refers to a scale of length that is a thousand times smaller than the micro scale. One nanometer is one billionth of a meter. Nanometers have traditionally been associated with the electronics industry. Viruses and DNA are examples of nanoscale natural objects; in contrast to these molecules, human cells can seem impossibly huge. The term nanotechnology refers to the engineering, measurement, and understanding of nanoscale materials and devices. The nano world is very different from the world around us. In the nano world, a physical model known as quantum mechanics may dominate over classical physics. Quantum mechanics is a large and complex field in which matter can behave very differently in terms of electrical and mechanical properties. Other properties, such as temperature, also cannot be defined by classical methods and must be considered in new ways. This phenomenon has a huge impact on the electronics industry, as quantum electronics could unlock untapped computing power.
Nanotechnology represents an entire field of science and engineering, not a single product or family of products. Therefore, there are many different types of nanotechnology, and many applications associated with each type. In addition, there are many different types of nanoscale objects around us, both natural and unnatural. For example, embedded nanotechnology covers electronics, optoelectronics, building materials, and sports equipment. Films and coatings cover self-cleaning coatings, waterproofing, antimicrobial coatings such as medical equipment, food containers, and appliances. Biologically natural nanotechnology deals with DNA and viruses. Unintentionally created particles deal with metal smelting and the combustion of fossil fuels, including gasoline and diesel. Natural particles deal with particles released from volcanic eruptions and wildfires. Manufactured particles address food and cosmetic additives, such as sunscreens, antimicrobial uses, and pollution cleanup. Nanoelectromechanical systems (NEMS) address drug delivery and diagnostic smart sensors.
There are many areas of nanotechnology. For example, microelectromechanical systems, or MEMS for short, studies safe drug delivery processes, and micro-mimetic robots. Manipulating flat, single-crystal atoms at the atomic scale and creating features at the atomic or “nano” scale is now a proven technology. The catalog of applications that utilize nanotechnology continues to grow. The National Nanotechnology Initiative, which coordinates nanoscale science across 26 U.S. federal agencies, defines nanotechnology as: “the understanding and control of matter at scales of approximately 1 to 100 nanometers, and the unique phenomena that enable new applications.” Nanotechnology is unique in that it enables many uses and applications that are not possible with conventional materials. Applications that utilize the chemical properties of matter require smaller amounts of nanomaterials than traditional materials. The chemical reactivity of a material is related to its surface area relative to its volume. The surface area per unit volume of nanoparticles is enormous.
The amount of nanoparticles in a material can be determined by the mass fraction of the nanoparticles, which means the weight of the nanoparticles relative to the total weight of the material, or by the ‘particle number distribution’, which means the number of nanoparticles relative to the total number of particles. Most measurement methods produce an intensity-weighted size distribution. For every material, there is a relationship between these different size distributions, but in general, this relationship is not known and therefore the different size distributions cannot be directly converted. Many materials can be engineered into nanoparticles, with the most common being silver, carbon, zinc, silica, titanium dioxide, gold, and iron. In general, these materials are small clusters of atoms. Carbon can also be made into hollow balls or tubes of atoms collectively known as fullerenes. Silver is effective at killing microorganisms and is used to keep food appliances sanitary, while iron is used to decontaminate contaminated land. Fullerenes have a wide range of electrical and mechanical properties and have many potential applications.
The biggest advantage of nanotechnology comes from the fact that it can greatly expand the well-used toolkit in materials science, as the essential structure of a material can be tuned at the nanoscale to achieve specific properties. Nanotechnology can be used to effectively create materials with a wide range of properties, such as being stronger, lighter, more durable, more responsive, more flexible, or better conductors of electricity. Nanoscale additives in polymer composites used in baseball bats, tennis rackets, motorcycle helmets, car bumpers, luggage, and power tool housings. Nanoscale additives can simultaneously improve light weight, stiffness, durability, and resilience. Nanoscale surface treatments on fabrics help prevent wrinkles, stains, and bacterial growth and reduce ballistic energy deflection in personal body armor. Nanoscale thin films on eyewear, computer and camera displays, windows, and other surfaces can provide features such as water repellency, anti-reflection, self-cleaning, UV or infrared resistance, anti-fog, antibacterial, scratch resistance, and electrical conductivity. In cosmetics, nanomaterials can provide transparency or coverage, cleansing, absorption, customization, antioxidant, antibacterial, and other health benefits in sunscreens, cleansers, complexion treatments, creams and lotions, shampoos, and specialty makeup. These are just a few of the benefits of nanotechnology.
In addition to these benefits, nanomaterials can also pose a threat to our health and safety. Health and safety aspects include the inherent hazard patterns of nanomaterials, exposure at the worker, consumer, and waste stages, and applicable risk management measures. Hazards are determined by the properties of the substance itself; however, these properties only result in a health or environmental hazard if some part of the human body or environment is exposed to the nanomaterial and can have a corresponding harmful effect; risk is determined by the combination of hazard and likelihood of exposure. The pattern of hazard varies greatly among nanomaterials. In an opinion letter dated January 19, 2009, the Scientific Committee on Emerging and Identified Health Risks (SCENIHR) concluded: “Health and environmental hazards have been demonstrated for a variety of manufactured nanomaterials. The hazards identified are indicative of the potential toxic effects of nanomaterials on humans and the environment. However, not all nanomaterials cause toxic effects. The hypothesis that smaller nanomaterials are more reactive and therefore more toxic cannot be substantiated by published data. In this respect, nanomaterials are similar to ordinary materials, some of which may be toxic and some of which may not. As there is not yet a generally applicable paradigm for identifying the hazards of nanomaterials, it is recommended that risk assessment of nanomaterials be approached on a case-by-case basis.” Monitoring developments in this area will be key to keeping the highest potential risks at the top of the risk assessment agenda. Recent reviews of the potentially harmful side effects of nanotechnology have shown that nanomaterials can pose risks to human health and the environment under certain circumstances. These findings emphasize the important role that nanotoxicity research can play in the responsible development of nanotechnology and the significant benefits it can provide to society.
“The hope is that nanotechnology will allow governments to put structures in place, both in Korea and internationally,” said Peter Grutter, a physicist at McGill University. In fact, nanotechnology is much more than what we’re discussing here. The applications of discovering and harnessing new properties of matter are nearly limitless, which is why nanotechnology is often referred to as a “platform” technology that can be easily fused and converged with other technologies to transform almost anything. Nanofrontiers participants focused on key areas where nanotechnology is expected to have a major impact soon. The impact of nanotechnology on many other fields, such as textiles, paper, food manufacturing, and agriculture, was not explored in much depth. Although advances in computing and electronics are occurring rapidly, these applications of nanotechnology were not chosen as the focus of the conference.
