Gigantic Challenges, Nano Solutions

The Science and Engineering of Nanoscale Systems

Maher S. Amer

• Publisher: Jenny Stanford Publishing
• Year: 2021
• ISBN:
  9781000346374
• Edition: 1
• Topic: Physical Sciences
• Subtopic: Chemistry
• Index: Chemistry

For the past three decades, nanoscale science and engineering have provided many systems with unique and unprecedented properties, illustrating that these will definitely determine the trajectory of science and technology for years to come. This book is the first textbook to introduce nanoscale systems in a pedagogical, and not research, style. Through ample examples and problems, it emphasizes the difference between bulk and nanoscale systems from a thermodynamic viewpoint and illustrates the process when a bulk system enters the nanoscale domain. It also brings together results of state-of-the-art research and provides the reader with the scientific foundations of such results. It introduces the fundamental thermodynamic treatment of nanoscale systems as well as the structure, properties, and performance of the three different types of fullerenes, namely, spherical, cylindrical, and planar or graphene. In addition, it discusses 2-D materials systems based on such building blocks. Finally, it shows the thermodynamic criteria allowing nanoscale performance in physically huge systems.

Chapter 1 Introduction and Overview

This chapter introduces nanotechnology and emphasizes the fact that it is more related to the thermodynamic behavior of small systems than to the physical dimensions of a system. It discusses the importance of entropic forces in such systems and presents examples of how such forces can alter the behavior of materials systems and enable them to exhibit unusual chemical, physical, electrical, optical, and mechanical properties. It identifies and discusses the building blocks of nanotechnology. It also gives examples of biological and natural utilization of nanostructured system as well as recent engineering applications of such systems.

1.1 Origins of Nanotechnology

Almost fifty years ago, on December 29, 1959, Richard P. Feynman,1 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 entitled “There’s Plenty of Room at the Bottom_ An Invitation to Enter a New Field of Physics.” The lecture was published later in Engineering & Science, Volume 23, No. 5, (February 1960) and was republished again in 1992 as the topic it first introduced overwhelmingly dragged the attention of many of the scientists, politicians, and the public across the globe.

¹Richard P. Feynman (1918–1988) was born in New York City on 11th May 1918. He studied at the Massachusetts Institute of Technology where he obtained his B.Sc. in 1939 and at Princeton University where he obtained his Ph.D. in 1942. He was a research assistant at Princeton University (1940–1941), professor of theoretical physics at Cornell University (1945–1950), visiting professor and thereafter appointed professor of theoretical physics at the California Institute of Technology (1950–1959). Feynman received the Nobel Prize in physics in 1965.

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 those 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 spoke 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 dominating.

The term nanotechnology was actually coined in 1974 by Norio Taniguchi (1912–1988), a professor at the Tokyo Science University, Japan. The term nano is Greek for “dwarf.” Professor 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’,” Prof. 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.” Prof. Taniguchi was mainly using the term to describe possibilities in precision machining for 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^–9 of a unit. In 1974, Prof. 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 prospective 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 nanorevolution. 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 precision. 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 prospective.

Figure 1.1 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 prospective.

It has to be pointed out, however, that the pure mechanical viewpoint shaping Drexler’s proposed vision led to a long and heated debate between him and Richard Smalley. Richard Smalley, a professor of chemistry at Rice University who shared the Nobel Prize in chemistry, 1996, with Robert Curl, Jr. and Sir Harry Kroto for discovering the C₆₀ molecule (fullerene [60]), had very well-founded reservations on applying pure mechanical engineering principles to nanomachinery, 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 bases that his original ideas have been misunderstood. 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 to make tiny (bug-like) machines capable of replicating themselves, working miracles, but could run amok. Giving 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 demonstrating the general misunderstanding of nanotechnology is the winner illustration of the 2002 “Visions of Science Award” by Coneyl Jay shown in Figure 1.2. The illustration shows how the public, in general, imagined what nanotechnology is all about; a bug-like tiny machine injecting stuff in a red blood cell! Unfortunately, that was the general impression on nanomedicine.

Figure 1.2 Science art illustrating the perception of nanobots. Copyright © Coneyl Jay/Science Photo Library.

Such a simplistic understanding of nanotechnology bred enormous public concerns and suspicion. Well founded and justified concerns regarding the impact of nanotechnology on scientific, economic, ethical, and societal aspects of humankind future were raised and are still being debated. We will discuss these important issues in later sections of this chapter. At this point, however, it is beyond any doubt that what we decided to call a dwarf (nano) turned out to be a giant.

1.2 What Is Nanotechnology?

Nanotechnology has been described as the third industrial revolution in human history. As each of the previous industrial revolutions, it is expected to have a huge and long-term impact on all aspects of human life. In addition, and not surprisingly, the new technology has not been very well understood in some cases and has been misunderstood in many other cases. According to the USA National Science Foundation 2007 released statistics, the majority of Americans (54%) have heard “nothing at all” about nanotechnology. In this section, we will address the nature of nanotechnology in very simple, even layperson, terms. As Albert Einstein pointed out, one can claim knowledge of a subject only when one is capable of explaining the subject to one’s grandmother. Time has changed since the Einstein era and many of nowadays grandmothers have advanced degrees. While this makes it easier for new generations to claim knowledge, it might be the time to change the rule of knowledge claiming to state that one may claim knowledge of a subject only if one is capable of correctly explaining the subject to the public.

1.2.1 What Can Nanotechnology Do for Us?

Everything we deal with is either human-made (made by humans) or natural (made by nature). For example, a car is a man-made transportation means, while a horse is a natural one. Currently, cars are faster and much stronger than horses. However, cars are still not capable of sensing the danger down the road as horses do. Also, cars cannot take their passenger home while the passenger is asleep as horses do. In addition, horses are much safer to travel by since none of us has ever heard about an accident between two horses resulting in rider’s life loss! To this end, we can describe nanotechnology as a new level of knowledge that could enable us to bridge the gap between the capabilities of man-made and natural things. This would result in a new generation of regular size, and not tiny, cars capable of sensing the danger, driving home, and reducing or eliminating accidents due to operator errors. In addition, a more important and a major difference between man-made and natural things is their efficiency. Over billions of years, nature mastered the art of efficient design and operation. Humans, however, are still at the beginning of a learning curve in those regards. For example, the best gasoline car engine we currently make has an efficiency of 25% ~ 30%. Mechanical efficiency of athletes during running was measured to range between 47% and 62%. Other species and natural processes can even reach higher efficiency than that. This clearly demonstrates how crucial nanotechnology can be considering the energy crises our civilization is currently facing.

1.2.2 Where the Name “Nano” Came From?

The word nano is Greek for dwarf. This word was actually used to indicate the length unit equal to one billionth of a meter (10^–9 meter). In order to have a good idea of what this length actually is, let us consider a typical single human hair. This is about 50 to 100 micron which is 50 to 100 millionth of a meter. Hence, a single human hair would be 50 to 100 thousand times larger than a nanometer. Atoms and molecules are typically measured by a unit called the Angstrom, which is one tenth of a nanometer, or one ten-billionth of a meter. Fifty years ago, Feynman predicted, and more recently, many scientists observed that the behavior of material clusters on the 1 ~ 100 nanometer scale is essentially different from that of larger cl...

Table of contents

• Cover Page
• Half Title Page
• Title Page
• Copyright Page
• Table of Contents
• Preface
• 1. Introduction and Overview
• 2. Nanophenomena
• 3. Bulk Systems and Nanoscale Systems
• 4. Scales of Thermodynamic Inhomogeneity
• 5. Depletion Forces and Surface Tension Effects
• 6. Symmetry and Symmetry Operations
• 7. Fullerenes: The Building Blocks
• 8. Spherical, Zero-Dimensional, Buckminsterfullerenes
• 9. One-Dimensional Fullerenes, Carbon Nanotubes
• 10. Two-Dimensional Fullerenes, Planar Fullerene, or Graphene
• 11. Overview, Potentials, Challenges, and Ethical Consideration
• Index