Preface Free

When I (Darren) was a student majoring in chemistry, I could not understand why chemistry was called “the central science” and why it was told to me that chemistry was fundamental to everyday life. The content I was learning, although interesting, seemed unimportant. Balancing chemical equations, solving Lewis dot structures, and performing acid–base titrations in the lab seemed very far from things I could touch or see, and which affected the way my world worked. Even when I joined a research laboratory in organic chemistry as an undergraduate, where I made molecules of purported value to medicine and pharmaceuticals, the real-world relevance of what I was doing was not apparent to me. While this feeling was most likely born of inexperience, along with perhaps an unfounded lack of faith in the importance of fundamental research, the feeling was inescapable. After all, we considered it a success when we obtained a measly 10 milligrams of the product! (Enough to get a spectrum to prove that we made what we thought we made). Ten milligrams—about the mass of a few grains of sand—after 18 months and 16 painstaking synthetic steps! Ultimately, I knew that the knowledge I created would be of at least a little value to medicinal chemists working at pharmaceutical companies to develop drugs to treat life-threatening diseases. However, I wanted my research to generate results that I could see and feel, and which could lead to fundamentally new advancements in science and technology.

One of the benefits of starting research as an undergraduate (as I would encourage you all to explore!) was the ability to present my work at conferences. At these venues, attended by some of the top scientists in the world, I learned that my experience—not yet expertise—in making molecules was directly applicable to materials science, in particular the flavor of materials science where control over the nanostructure enabled the discovery of new, apparently magical, properties. After all, the reason I entered into science and technology was not for its practice, which involves the meticulous collection of data, but for the fact that it was the only legitimate route to magic and the fantasy world of Star Trek and Star Wars. Thus, it wasn’t until later into my undergraduate studies that I came to understand how phenomena and materials that occurred on the nanometer scale that gave rise to much of what motivated me to pursue a degree (and a life) in science and engineering.

Indeed, as we will see, phenomena that occur on the nanometer scale are the basis for all of modern computation, imaging, and human-machine interfaces; chemical catalysis, fuels, and materials manufacturing; drug delivery and tissue engineering; and technologies for the conversion and storage of energy (i.e., solar cells and batteries). These real-world applications are enabled by the physics that comes into play when objects become so small that their properties are dominated by atoms at their surfaces, or when electrons are confined to small spaces. With such small structures separated by even smaller gaps, seemingly insignificant forces arising from van der Waals interactions can challenge the strengths of the strongest bodybuilders.

At the intersection of physics, chemistry, and several sub-disciplines of engineering, nanoengineering is the manipulation or design of materials and phenomena that occur on the scale of roughly 1–100 nm to accomplish useful tasks. So, when in 2012, I got an offer to become an assistant professor in the Department of NanoEngineering at UC San Diego, I was home at last. Finally, a chance to do research and teaching at the very nexus of all that fascinated me as a student and researcher in my previous life! One of the purposes of this book is for me to share some of my excitement with you.

This book can be used to accompany either a one quarter (ten week) or one semester (fifteen week) introductory undergraduate course in nanoengineering. Such a course might be a core requirement of degree programs in nanoengineering, chemical engineering, or materials science, or as an elective in mechanical engineering, electrical engineering, or bioengineering. It can also be used in courses which teach wide-ranging STEM topics to non-STEM majors. Indeed, when I was a graduate student at Harvard, I served as the lead teaching assistant for such a course, Core Science A50: Invisible Worlds, taught by George Whitesides and Mara Prentiss. While such courses taught to freshmen are usually surveys of the broad application areas of nanoengineering with not much time for depth, I attempted to provide enough detail—enough to be “dangerous”—for the motivated students to dig deeper on their own. If survey courses present material in a form which is “a mile wide and an inch deep,” I hope that this course maintains a depth of at least several inches at most places. Thus, attention is paid to fundamental concepts that underlie all phenomena and applications. While concepts such as force, energy, entropy, electrostatics, quantum mechanics, and intermolecular forces play key roles, no prior knowledge or prerequisites beyond ordinary high school courses in chemistry, physics, biology, and math are required for the motivated students to develop a working knowledge of these topics.

A note to students: to achieve success in this or any course, it is essential to do some pre-reading before coming to class. A note to instructors: ideally, class time would be used to reinforce concepts using individual and team-based problems, multi-day design challenges, and discussion—the so called “active learning” or “flipped-classroom” approach. To read effectively, you should have a notebook to extract the main points and concepts and make bulleted lists where you summarize and connect concepts. Try to invent your own mnemonics or semantic associations (associate terms with people, places, objects, and events from your own life…or movie characters, songs, food items, etc.) for terms that are difficult to remember. Some students—including myself—like to put these notes on index cards (i.e., flash cards), which can be taken along on the bus or trolley. While I have tried to make the content accessible to the widest range of preparation possible, it is impossible to anticipate the depths of past courses taken by every student. Thus, if you see an unfamiliar term, feel free to look it up online or ask the teaching staff. I would encourage the use of generative AI (e.g., ChatGPT) to help you, but at the time of this writing, it provides lot of incorrect information on science topics, so it is crucial to cross-reference explanations with the book, other sources, or your own understanding.

While you read, be sure to write down every question you have. You can use these questions as the basis for “reading as detective work.” Sometimes the questions will be answered later in the book, and some questions will be best answered by discussing them with your study groups or by asking the teaching staff. It is best to focus your effort outside of class with an approach that is characterized by the activity of learning—which is an active process—as opposed to studying. The word studying often conjures a picture of a student staring at the book passively with an elbow perched on the desk with their hair clutched in their hand, in deep though, or—more likely—frustration. That is, aim to learn the concepts so that you can teach it to others in your class, rather than simply studying the material by staring at the pages.

This book is a product of my 22 years of work as a student, researcher, and educator in higher education in chemistry, engineering, and nanotechnology. The collection of topics in this book is idiosyncratic; another nanotechnology researcher/educator would have chosen a somewhat different collection of topics. My coauthor, Robert, a rising expert in the field of computational nanoscience, coauthored every chapter. He revised my drafts of Chapters 1–14 with an eye toward the best way to explain these concepts to first-time learners. He knows from experience as both a first-time learner and later as a teacher of this material: the first time I taught this class to undergraduates in the winter of 2017, Robert was in my class. Since then, he has served as a teaching assistant, and has nearly as many years of experience in applying and explaining the concepts in this book as I do. Robert also took the lead on writing Chapter 15, on computational nanoscience. As a non-expert in this area, I took the role of revising through the lens of a first-time learner.

You will notice that the “Further Reading” section at the end of each chapter is focused on only a few key entries per chapter. Its brevity arises in part because much of the knowledge in this book was synthesized by our experiences as professional researchers (and researchers in training) and from nearly 100 courses the two of us have taken and taught (as well as the two of us collectively having fallen into many thousands of rabbit holes on Science YouTube, Wikipedia, and ChatGPT). Nevertheless, there are some key books and articles which played a key role in shaping our intuition of many topics. We have highlighted these sources and also provided descriptions of where to find the relevant information within them and/or why we found them so valuable.

Finally, we tried to write the book that we would have wanted to read. We enjoyed writing it, and at times it felt autobiographical. To a great extent, it reflects the processes, mnemonics, and personifications of inanimate objects that led use to our own understanding of each topic. Ultimately, we hope that this book is interesting and inspires you to find your passion within the wide and fascinating field of nanoengineering.

Yours in Nano,

Darren J. Lipomi, Robert S. Ramji

San Diego, California