Nanotechnology, the Technology of Small Thermodynamic Systems

1.1 Introduction

This chapter introduces nanotechnology, emphasizing the fact that it is more related to the thermodynamic behaviour of small systems than to the physical dimensions of the system. The importance of entropic forces in such systems will be considered and examples of how such forces can alter the behaviour of materials systems and enable them to exhibit unusual chemical, physical, electrical, optical, and mechanical properties will be given. The building blocks of nanotechnology will be identified and discussed. Examples of biological and natural utilization of nanostructured system as well as recent engineering applications of such systems will be given.

1.2 Origins of Nanotechnology

Almost 50 years ago, on December 29, 1959, Richard P. Feynman, a great physicist and, later, a Nobel Laureate, gave a lecture at the annual meeting of the American Physical Society at California Institute of Technology, Pasadena, entitled 'There's Plenty of Room at the Bottom, an Invitation to enter a new field of Physics.' The lecture was published later and was republished again in 1992 as the topic it first introduced overwhelmingly caught the attention of many of the scientists, politicians, and the public across the globe.

The term "nanotechnology" was never used in Feynman's lecture; instead, Feynman spoke about miniaturization, emphasizing the important scientific and economic aspects of our ability to make things small. Small machines that are capable of making even smaller ones. In his own words 'although it is a very wild idea, it would be interesting in surgery if you could swallow the surgeon'. Not to be misunderstood, Feynman emphasized that such a vision necessitates an ability to manipulate materials systems on a small scale. Feynman would not have missed the obvious and logical fact that atoms and molecules behave differently when arranged in a small system compared to their behavior in large or bulk systems. In his famous lecture Feynman said:

'I can hardly doubt that when we have some control of the arrangement of things on a small scale we will get an enormously greater range of possible properties that substances can have.'

The obvious reason for that was:

"... Atoms on a small scale behave like nothing on a large scale, for they satisfy the laws of quantum mechanics. So, as we go down and fiddle around with the atoms down there, we are working with different laws, and we can expect to do different things.'

Hence, while Feynman did not explicitly speak about what is referred to nowadays as "nanotechnology," he pointed out a new and important domain of physics where matter is investigated on a new scale at which quantum effects are dominant.

The term nanotechnology was actually coined in 1974 by Norio Taniguchi (1912–1988), a professor at Tokyo Science University, Japan. The term nano is Greek for "dwarf". Professor's Taniguchi's main interest was in high precision machining of hard and brittle materials. He pioneered the application of energy beam techniques, including electron beam, lasers, and ion beams, to ultra-precision processing of materials. In his famous paper entitled 'On the Basic Concept of 'Nano-Technology'', Professor Taniguchi defined the field as:

'Nano-technology mainly consists of the processing of, separation, consolidation, and deformation of materials by one atom or by one molecule.'

Professor Taniguchi was mainly using the term to describe possibilities in precision machining for the electronic industry to enable smaller and smaller devices down to the nanometer length scale. The prefix nano is known in the metric scale system to represent a billionth or 10~ of a unit. In 1974, Professor Taniguchi was interested in precision machining down to the nanometer level, which requires an ability to manipulate materials on the atomic or molecular level.

In 1986, K. Eric Drexler reused and popularized the term "nanotechnology" in a much broader prespective describing a whole new manufacturing technology based on molecular machinery. The premise was that such molecular machinery does exist, by countless examples, in biological systems, and, hence, sophisticated, efficient, and optimized molecular machines can be produced. In a series of books, Drexler described a number of possible molecular machinery suitable for a very wide range of applications. He also described 'profiles of the possible' as well as 'dangers and hopes' associated with the nanotechnology. Drexler was awarded a PhD in 1991. His work, indeed, triggered and inspired what is currently referred to as the nano-revo-lution. He adapted the viewpoint that although nanotechnology can be initially implemented by resembling biological systems, ultimately it could be based on pure mechanical engineering principles, rendering nanotechnology as a manufacturing technology based on the mechanical functionality of molecular size components. Such mechanical components, i.e., gears, bearings, motors, and structural members, would enable programmable assembly with atomic precission. Figure 1.1 shows the three scholars Richard Feynman, who first envisioned nanotechnology, Norio Taniguchi, who coined the term nanotechnology, and Eric Drexler, who popularized the term in a new perspective.

The pure mechanical viewpoint shaping Drexler's proposed vision led, however, to a long and heated debate between him and Richard Smalley. Richard Smalley – a professor of chemistry at Rice University who shared the 1996 Nobel Prize in Chemistry with Robert Curl, Jr. and Sir Harry Kroto for discovering the C0 molecule (fullerene [60]) – had very well founded reservations on applying pure mechanical engineering principles to nano-machinery, and on the premise of mechanical functionality of molecules. The debate was indeed a significant controversy about nanotechnology's meaning and possibilities. Drexler, later, backed off of his position on the basis that his original ideas have been misunderstood. Several analyses of the debate were published. Unfortunately, the debate left a negative impression on public view of the technology and, to a large extent, deepened the wrong concept that nanotechnology is the technology by which to make tiny (bug-like) machines capable of replicating themselves, working miracles, but that could run amok. Given the effective role media usually play on public viewpoint and understanding of science, it was concluded recently that the media has contributed to bounding nanotechnology by representing the term as a technology that trades on ideas of wonder as well as risk.

A good example that demonstrates the general misunderstanding of...