Size Really Does Matter

The Nanotechnology Revolution

Colm Durkan

• Publisher: WSPC (EUROPE)
• Year: 2019
• ISBN:
  9781786346636
• Topic: Physical Sciences
• Subtopic: Nanoscience

Nanotechnology is a buzz word many of us have heard but are uncertain what it really means. This book works to dispel the myths and unravel the truth about this branch of science and technology that has already touched many aspects of our lives, from cheaper and faster medical diagnostic tools and more effective ways to deliver existing ones to helping to create new medicines and electronic devices.

Size Really Does Matter starts by looking at the science and history of nanotechnology, followed by real-life examples of how it is used, what cutting-edge research is being carried out and why, and potential risks of this exciting new technology.

It is written in an accessible style with genuine enthusiasm for the topics it addresses, including how nanotechnology hopes to address problems in several fields, such as cancer research, novel devices, new materials and improved manufacturing methods for existing products.

Dr Colm Durkan talks about this book on the University of Cambridge's website

Contents:

• Preface
• About the Author
• Introduction
• There's Plenty of Room at the Bottom
• The Science Bit
• Nanomaterials
• Seeing at the Nanoscale
• Nanotechnology in Electronics
• Nanotechnology in Healthcare
• Concluding Remarks
• Index

Readership: General audience interested in nanotechnology and its relation to everyday life.Nanotechnology;Nanoscience;History of Science;Nanomedicine;Nanomaterials;Quantum Mechanics0 Key Features:

• Written in an accessible style
• Full of color figures and graphs illustrating key points
• Refers to everyday issues as much as possible

Chapter 1

Introduction

We exist in a universe governed by the rules of quantum mechanics. Rules that we unfortunately do not understand and may never be able to. At the turn of the 20th century, the development of quantum theory led to the first steps toward nanotechnology. This theory is all about the physical rules that fantastically small things are seen to obey. These rules are different from what we encounter in our everyday lives as they relate to effects that are too small to see directly. They do, however, become important once we are dealing with nanometer-sized things, which is what nanotechnology is all about.

It is at the boundary of existing knowledge where the most useful and significant discoveries are often made, and this is what makes nanotechnology so exciting — it is concerned with the nature of things that are a few nanometers across, and encompasses physics, chemistry, biology, medicine, and engineering. In fact, the Nobel Prize for chemistry in 2016 was awarded to three nanotechnologists for their pioneering work in creating molecular machines, which we will explore in Chapter 4.

The word Nano comes from the Greek “Nanos” meaning “dwarf”, and in the scientific context the prefix nano is used to indicate one billionth (a billion being a thousand million). One nanometer, abbreviated as nm is therefore one billionth of a meter. Nanotechnology is defined as the ability to both create and study objects with at least one dimension in the size range 1–100 nm. The diameter of a strand of DNA — our genetic blueprint is 2 nm, and the spacing between atoms in a typical solid material is around a fifth of a nanometer. In much the same way as getting to grips with the size of the universe is challenging for us — we know that it is at least 46 billion light years across, perhaps even infinite (we don’t actually know!); the size of things down at the atomic scale is so small that we find it equally hard to envisage. We can explore the observable universe using telescopes, and similarly we can explore the nanometer world using microscopes. This is a key element of nanotechnology and nanoscience as we will see, particularly in Chapter 5. A useful guide as to the relative size of everyday objects from 1 m down to 0.1 nm is shown in Figure 1 which was produced by the Royal Society in 2004.

Figure 1. Length scale showing the nanometer in context. The length scale at the top ranges from 1 m to 10^–10 m, and illustrates the size of a football compared to a carbon 60 (C60) molecule, also known as a buckyball. For comparison, the world is approximately 100 million times larger than a football, which is in turn 100 million times larger than a buckyball. The section from 10^–7 m (100 nm) to 10^–9 m (1 nm) is expanded below. The lengthscale of interest for nanoscience and nanotechnologies is from 100 nm down to the atomic scale — approximately 0.2 nm.

Source: Relative scales schematic from the Royal Society report “Nanoscience & nanotechnologies: opportunities and uncertainties”, 2004.

While we are thinking about ridiculously large numbers and small things, an example is to consider roughly how many atoms are in a typical person, say, me. We will do this by working out the ratio of my volume to that of a single atom, which should equal the number of atoms in me. I weigh approximately 73 kg, and given that the density of the average human is 0.98 times that of water (which is 1000 kg per cu. m at 20°C), my volume = mass/density = 73 kg/(0.98 × 1000 kg per cu. m) = 0.07 cu. m. The volume occupied per atom in a material is around 10^–29 cu. m, meaning I contain approximately 0.07/10^–29, or 7 × 10²⁷ atoms, which is 7 billion billion billion atoms (Figure 2). An enormous number to be sure, but this is nothing compared to the number of bacteria on the planet, which is estimated at around a thousand times more, or 5 × 10³⁰. If I were to take each of those atoms in me and spread them out in a line with their typical spacing of around 0.2 nm, then that line would be 1.4 × 10¹⁸ m long, which is 149 light years, almost long enough to get us to the Hyades star cluster in the constellation Taurus.

Figure 2. The approximate number of atoms in my body: 7 × 10²⁷.

I have been working in nanotechnology since the mid-1990s, and in the short time from then until now, have seen a renaissance in the way we do science and in how it is communicated to a wider audience. I have seen scientists treated simultaneously with respect, contempt, and distrust, and have had many fascinating conversations with all sorts of people who really just want to know more. I have met those who believe science is a mere vanity and utterly useless and those who believe we have a duty to society to share our knowledge and dig deeper. Why does mankind strive to climb our planet’s highest mountains, to dive to the ultimate depths of the sea bed, or to travel out to space? Do we actually learn anything about this apart from how fragile human life is, how tenacious life in general is, and how small we are in the grand scheme of things? These are difficult questions to answer but they do need to be asked. All I can say is that it is part of the human condition to question and want to know more about our surroundings, both near and far. Without this thirst for knowledge, I have no doubt we would still be swinging out of trees in the jungle. As an academic, I may of course be viewed as part of the establishment, but I can see the merit of all sides of this argument and that it is not so simple — some research is almost certainly never going to lead to any useful outcomes (This is not always known at the time of course), and yes, we do have a duty to wider society to use our funding responsibly and communicate our findings in as accessible a manner as possible.

It was at the age of around 12 that I became interested in science when I was given a copy of a new magazine called Science Now, a Marshall Cavendish publication that ran weekly. There were articles on sharks, astronomy, aeronautics, space exploration, medical advances, and all manner of things that were just of general interest, but they got me wondering about how things work. Rather than go down the path of engineering (which I now teach), I chose to pursue physics, as to be honest, as a teenager growing up in Ireland, I thought engineers were the people who fixed washing machines and boilers. I still meet those who think the same and it’s no surprise, as the word is constantly misused. On the continent, engineers and scientists are placed on the same level socially as doctors and lawyers, respected and considered to be essential cogs in the machinery of a well-functioning society, whereas in the British Isles, we seem to have lost this sentiment some what, so it is time to earn it back. The world is not full of mad scientists sneaking around trying to make new discoveries at all costs, not caring about ethics or the effect on the world, apart from the unscrupulous few. We are just normal people who have a burning curiosity about how things work and want to find out more with the overarching aim of wishing to use that knowledge for the greater good. The ultimate reward for any scientist is to do something which is useful to people in their everyday lives. This can be seen by others as quirkiness but I would rather label it as tenacity and an ability to focus. In my case, the initial interest in physics led me down a wandering path where my work straddles physics, chemistry, materials science, engineering, and biology, with a single common thread running through it all. I am fascinated by microscopic things, i.e. things too small to see with our own eyes. In fact, I am most interested in things that are even smaller than just microscopic, and we could describe as nanoscopic. By virtue of their size, things this small have revolutionary properties and my job in writing this is to convince you that not only is this useful and in fact is already being used in a vast number of cases, but it will also change the way we view the world around us. The world and in fact the universe is utterly beautiful in its complexity, and this is only enhanced as our understanding deepens. The fact that we have developed sufficient insights in the past few millennia to be able to explain everyday things is a marvel. A common mistake of the less scientifically literate is to believe that the world must be very dull to scientists as there is less mystery in what we observe. We understand why flowers are the color they are and how this has evolved to attract the right kind of insects or pollinators, how the tides work, how the stars and planets move across the sky, how the sun works, how to predict the weather, etc. The fact that there are patterns in nature that we can describe using models that make sense is where the true beauty of nature lies. Some of the subtler intricacies of nature are only revealed at nanometer scales, hence my assertion that by finding out more about it, we will start to understand more about the world around us and look at it through a different lens. So, in a nutshell, this is a book about nanotechnology and how it affects our lives now and how it will facilitate new developments in the future.

Nanotechnology is everywhere. That sounds a bit dramatic to say the least. It is however, true. I had better expand on what I mean by everywhere so we don’t get carried away before we even start. I really mean that nanotechnology has in some way touched on many aspects of our daily lives, in mostly good ways, although not always so. We live in an age where many things are transient and immediate, including knowledge, with the result that the subtleties of nature can easily be overlooked unless we take a step back and look closely. At the same time, we are making great strides in technology, particularly artificial intelligence (AI), machine learning, and the internet of things. We have harnessed the power of the atom both for great good (atomic energy) and great harm (nuclear weapons). Many of the technologies of the modern age that we now take entirely for granted have been made possible through advances in manufacturing of electronic devices and components and the discovery of new materials — from composites to graphene. Out of these early developments, nanotechnology was born and has infiltrated all industry sectors, running in the background. This may sound sinister, but actually nanotechnology is in many ways obvious as we will see — it is an approach to doing things that makes optimum use of the strange and wonderful properties of materials when they are made very, very small.

Continuous developments in science and technology have inexorably led us to the point where we have kept making things smaller and smaller. This is particularly so in the electronics industry where individual circuit elements have become small enough that the size of individual atoms is noticeable and starts to matter. This is also the size or lengthscale where the quantum nature of our world is revealed, and that is no coincidence. As we will see later, quantum mechanics may be entirely freaky and weird, but it is also unquestionably correct. We therefore need to get to grips with what it all means as we are in the middle of a step change in our technological capability as a result of it.

Now we can start to delve a little deeper in our quest to find out what nanotechnology is. If I give you a hint — the nano bit is a measure of size — the nanometer. Nanotechnology is all about the science and technology of things whose size we measure in nanometers, which is 1 billionth of a meter. You have probably heard or read something about nanotechnology, ranging from the preposterous to the downright terrifying, and possibly loosely based on some half-truths or dare I say, alternative facts. For a while in the late 1990s and early 2000s, nanotechnology was touted as the next best thing that would revolutionize our world, and then the promise turned to suspicion akin to that encountered by the field of genetic modification in crops. Thankfully, we seem to be out of the woods and nanotechnology is again being seen as inevitable and something to be considered and harnessed rather than feared and fought.

Nanotechnology is a form of technology that has become pervasive. It already affects our daily lives in many sectors including but not limited to cosmetics, packaging, construction, healthcare, art materials, defense, oil and gas, energy storage, and clothing. This is captured in Figure 3.

Figure 3. The application areas where nanotechnology is most used.

The aim of this book is to explore this in a systematic way. In the course of this, I will dispel some myths that have arisen. One example of this has got to be one of the most annoying misconceptions about nanotechnology that I feel duty bound to dispel the myth entirely. There have been many very nice artists’ renditions in a variety of journals and newspapers over the last 20 years depicting tiny robots moving around in our bloodstream repairing damaged cells and tissues, and this idea was originally touted by nanotechnologists seeking funding for their research. While nanotechnology is and will continue to lead to major breakthroughs in medicine that are actually useful, it is not sensible to think of nanorobots going around our bodies repairing damaged cells. This is a compelling idea and there’s no doubt, Hollywood has used this concept time and time again, in otherwise quite cool and fun movies. But it’s just wrong! It has nothing to do with nanotechnology. I’m not saying it’s impossible, but I am saying that it is highly unlikely — there are much better ways of healing where we use nature or medicines rather than machines. Let’s not fill our and our children’s heads with stuff that’s just complete twaddle and try to get it right!

I have written this book as a story — how we came to realize that the world around us is far more complex than it appears, and that it is in fact really quite beautiful in the patterns that appear in the laws of nature, with an eye on all things nano.

I will focus on the development of nanotechnology with the emphasis on things that have recently been discovered and are either under development in research labs or employed in industry, and therefore in everyday life. I am not so interested in speculating about things that may or may not happen, no matter how exciting they may sound. Nanotechnology as a topic is vast, so in order for this book to not be thousands of pages long and utterly disjointed, I will concentrate on those aspects that I consider most important.

My own research is firmly rooted in a basic-principles approach which is applied to fields as diverse as quantum devices, understanding fouling in oil-exposed pipes, the effect of various common treatments on the molecular-scale properties of hair and teeth, and a whole host of things to do with how molecules of all kinds interact with surfaces of all kinds, as this is a surprisingly common problem. The inevitable price I will pay for this cherry-picking approach is that I will leave things out and somebody somewhere will say “hey, why didn’t you mention space travel or batteries or invisibility or …”. However, the purpose of this book is that once you have read it, if you come across some headline or other that talks about the latest breakthrough in nanotechnology, you will have gained the tools to analyze it critically and make up your own mind. I will not draw on hard numbers for many things as they simply don’t exist. The topic is highly conceptual, but there are lots of everyday examples that we can look at to illustrate all of the relevant points. Nanotechnology is about making and using nanometer-sized things, which means very, very small things just a bit bigger than single atoms. The size or lengthscale of objects are absolute but our perception of them is subjective from the point of view that while there is no doubt 1 nm is pretty small, it is enormous compared to the suspected size of an electron, proton, neutron, or Higgs Boson, which are at least a million times smaller. For people working in particle physics, a nanometer is huge, whereas to people working in cosmology, the size of our solar system is tiny, never mind a nanometer!

Why then is the nanometer an important lengthscale — who cares? This is what we will look at in this book, at the fact that the properties of matter are to a large extent determined by phenomena at the nanometer scale. It is no coincidence that some of the fundamental lengthscales of physics and chemistry happen to be in nanometers. What I mean by lengthscales is that once objects are within a range of sizes, certain effects start to be noticed. For example, the wavelength of waves on the surface of the sea is of order 10 m. If we are on a large boat, for instance, the new Queen Elizabeth aircraft carrier which is 280 m long, then we will not notice those waves at all. On the other hand, if we were in a small boat, say 5 m long, then we will be thrown all over the place by those waves. Another example is the size of an atom — around 1/10 of a nanometer. If we were to somehow have an atom thrown at us, we would not even notice it. However, if we were to throw that atom at another atom, they would both know about it. It is all to do with the relative sizes of things or characteristic distances over which certain effects are noticed. It turns out that there are a few of these lengthscales in physics, and they happen to be in the range of nanometers, and that is why nanotechnology even exists. An example of something that has dimensions in nanometers is DNA — our genetic blueprint consisting of two long molecular strings, collectively called a double helix. This has an average diameter of 2 nm (Figure 4). Size therefore is entirely relative and really does matter.

Figure 4. DNA — without a doubt the most important nanostructure!

As it turns out, because of this issue to do with lengthscales, things that are small enough to talk about their size in terms of nanometers have very different characteristics and properties (in terms of their strength, color, chemical reactivity,...