Nanoparticles

Raz Jelinek

• Publisher: De Gruyter
• Year: 2015
• ISBN:
  9783110389913
• Edition: 1
• Topic: Physical Sciences
• Subtopic: Nanoscience

Nanoparticles presents the remarkable variety of nanoparticle families, compositions, structures, and functions. The book discusses nanoparticles made of semiconductors, metals, metal-oxides, organics, biological and hybrid constituents.
Through a wealth of examples and case studies, supplemented by numerous
figures, readers that are not necessarily active or experts in this area acquire a
broad overview of this exciting field at the interface between scientifi c research and practical technologies.
The contents summarize the contributions to this field of diverse scientific and technological disciplines - chemistry, physics, biology, electronics and others providing a comprehensive knowledge - the types of nanoparticles, their compositions and how the relationships between the atomic constituents affect their properties, as well as potential applications of nanoparticles.
- Covers diverse uses of nanoparticles in scientifi c research and industrial applications, underscoring their extraordinary diversity and potential utilization.
- Experimental and conceptual approaches applied to the study of nanoparticles are discussed extensively. Additional references provide the reader with a basis for further study.
- Also available by Professor Jelinek: Biomimetics - A Molecular Perspective (2013), ISBN: 978-3-11-028117-0

1 introduction

For a young scientific discipline which burst on to the stage less than 30 years ago, nanotechnology has had a tremendous impact on both fundamental research and development of technology. Nanoparticles (NPs) have been among the most visible facets of nanotechnology research. The essence of this field is the realization that the properties of matter are often significantly altered as one ventures into the nanoscale. Indeed, the unique properties of NPs are due in large part to their nanometer (10^-9 meter) dimensions. The interest and activity in this field have led to dramatic contributions in diverse fields of science and technology - chemistry, physics, biology, electronics, and others. In fact, NPs can be considered both products and promoters of the “nanotechnology revolution”, as attested by the huge body of work on the subject.

Although the precise definition of NPs may be somewhat fluid, this book focuses on atomic and molecular aggregates which are generally smaller than tens of nanometers. While the term “nanoparticle” often evokes an image of a small spherical particle, this book is not limited to spherical NP configurations. The discussion rather spans the diverse structural universe of nanoparticles, including (nano)wires, rods, stars, cubes and various other morphologies enabled by nature, our imagination, and synthetic acumen. This book is designed to be an introductory textbook to the rapidly evolving field of nanoparticle science and technology. As such, the book aims to present different facets of nanoparticle research to readers who are not necessarily active or experts in this discipline. A scientific knowledge base, however, is quite essential for grasping many of the subjects discussed. Overall, this book aims to endow the reader with a methodical summary of the field - how concepts, synthesis schemes, and applications of NPs have been developed and implemented.

Discussion of the broad and diverse array of systems and experimental strategies is carried out primarily through presentation and analysis of studies published in the scientific literature. Starting from a historical perspective, the book has several underlying themes, including synthetic routes for preparing NPs; different NP structures and the way the structural and morphological features of the particles affect functionalities; novel constructs and devices utilizing NPs; and the use of NPs beyond the nanoscale - as building blocks in higher-order materials. Specific emphasis is placed upon the interface and relationships between NPs and biological systems, as important developments of biomedical applications underscore both the potential and risks associated with increased applications of NPs as therapeutic and diagnostic tools. While unique physical phenomena are intrinsic to the properties and applications of NPs, detailed analyses of the physics aspects of NPs are beyond the scope of this book.

Naturally it is difficult to cover all pertinent topics and aspects in a single textbook. Accordingly, this textbook will hopefully serve as a “starting point” for nanoparticle science and technologies; the reader is accordingly referred to many excellent comprehensive reviews and scientific publications, outlined in the “Further reading” section at the end of the book. Importantly, the focus here is on nanoparticles and not “nanoscale materials” as a whole. Accordingly, discussion in the text is focused mostly on “stand-alone” synthetic NPs self-assembled in solutions, rather than nanostructures produced via techniques such as lithography which can technically be perceived as parts of larger entities (e.g. surface). This book also excludes the huge field of “carbon nanomaterials”; carbon nanoparticle allotropes, such as fullerenes and carbon nanotubes, exhibit distinct properties related to the organization and binding of carbon atoms and deserve an independent textbook.

The chapters in the book are devoted to different nanoparticle compositions and types: semiconductor NPs (Chapter 2), of which “quantum dots” occupy a prominent position; metal NPs (Chapter 3), including the highly diverse applications of gold, silver, and transition metal NPs; metal-oxide NPs (Chapter 4) employed in varied technologies such as solar energy harvesting and biomedical imaging; biological and polymer NPs (Chapter 5), in which organic building blocks have been used to construct nanoparticles; hybrid NPs (Chapter 6), comprising more than one component and displaying intriguing configurations - from core-shell NPs, all the way to more exotic species, such as “nanostars”, “nanodumbbells”, nanocages, and others. A specific chapter is devoted to the effects of nanoparticles on biological entities - cells, proteins, and DNA (Chapter 7); and the last chapter focuses on the use of NPs as building blocks for larger and more complex materials (Chapter 8). A certain overlap naturally exists between topics. Thus, for example, NP assemblies are discussed both in a dedicated chapter (Chapter 8), as well as in individual chapters (such as solar cells comprising of titanium oxide NPs). Similarly, the interface between NPs and the biological world is a vast and recurring theme in several chapters; the significance of this topic is also reflected in a thorough discussion in a specific chapter (Chapter 7).

Nanoparticles have inspired the scientific and technological communities for several decades now, and the sheer activity in this field promises to continue generating new discoveries, revolutionary products, and novel physical phenomena. The remarkable progress in our understanding of NPs and the ability to control and modulate their properties will undoubtedly further expand the frontiers of chemistry, physics, material sciences, and biomedicine.

1.1 Historical context and early work

“Pornography is a matter of geography” as the saying goes; this aphorism might seem relevant to many scientific disciplines in which long-known phenomena are explained using new physical and chemical tools and new terminology. This has also been partly the case with nanoparticles. Indeed, NPs have been produced since mankind learned to manipulate materials, although the actual term (and hype ...) of “nanoparticles” was coined much more recently. One of the earliest and most famous examples of the use of NPs for everyday objects was the “Lycurgus Cup” (Fig. 1.1). Manufactured by a Roman craftsman almost 2000 years ago from special glass speckled with “gold and silver dust”, this extraordinary object changes its color depending on the position of the incident light. When illuminated from the outside, the cup appears green, however when the light source is placed inside the cup it shines red. This rather unusual property is directly related to the interplay between reflection and scattering of the light beam from metal nanoparticles embedded within the glass. The Romans did not of course know they were working with NPs, and in fact the unique mechanism responsible for the optical properties of the Lycurgus Cup was deciphered not that long ago. However, the Lycurgus Cup illustrates a notable facet of NP science and technology - that varied chemical and physical phenomena associated with NPs have, in fact, been known for quite a long time. Indeed, part of early NP research was aimed at providing a solid physical/chemical understanding of known processes and materials.

Fig. 1.1: The Lycurgus Cup. Image provided by the British Museum.

In a historical context, NP research emanated in large part from a convergence of two distinct scientific disciplines - the study of atomic clusters, and colloids research (Fig. 1.2). Clusters are loosely defined as aggregates of relatively small numbers of atoms, held together by both noncovalent and covalent bonds (Fig. 1.3). Importantly, it has been determined that clusters possess different physical properties, both compared to individual molecules, as well as in relation to the bulk material. In particular, scientists concluded that the unique characteristics of atomic clusters can be largely traced to the significantly high ratio between atoms at the surface of a cluster and its inner core. Indeed, this (high) ratio is a major determinant distinguishing clusters (and nanoparticles) from their bulk counterparts.

Colloid research is the other major preceding field which led to the emergence of nanoparticle science. Colloidal systems are defined as molecular aggregates which are usually dispersed within a more abundant substance (such as a solvent. Milk is a prime example of an aqueous colloidal suspension). Indeed, colloid dispersions are among the bedrocks of metallurgy and materials science in general. While colloids have been prepared routinely for millennia, the advent of science and technology has brought about the realization that the properties of colloids, particularly particle size, have intimate relationships with the overall functions and macroscopic characteristics of colloid assemblies. This link between the size of colloids and their overall material properties is one of the most important aspects of NP research, and is a fundamental phenomenon manifested in different NP systems presented throughout this book. Milk, in fact,...

Table of contents

• Also of Interest
• Titel
• Impressum
• Preface
• Inhaltsverzeichnis
• 1 introduction
• 2 Semiconductor nanoparticles
• 3 Metal nanoparticies
• 4 Metal oxide nanoparticles
• 5 Organic and biological nanoparticles
• 6 Hybrid and composite nanoparticles
• 7 Nanoparticle interactions with biomolecules and cells
• 8 Nanoparticle assemblies
• Further reading
• Index