| The focus of nanoscience and nanotechnology is gradually shifting from the synthesis of individual components to their assembly into larger systems and nanostructured materials. After over two decades of intense research, there are now hundreds if not thousands of procedures available that allow for crafting the sizes, shapes, material properties, or surface chemistries of nanoscopic particles. With these building blocks in hand, the major challenge facing nanoscience is to develop efficient and robust ways of assembling nanocomponents in order to develop new solutions for medical diagnostics,65-67 drug delivery,68,69 sensors,70 electronic devices, 71,72 or new materials of unique properties.73 Self-assembly 74,75 is arguably the most promising candidate for this task as it can, in principle, evolve large numbers of individual particles of appropriately chosen properties into higher-order structures. The success of this approach depends crucially on our ability to understand and "engineer" the interactions between nanoscopic particles.;The starting point of this Dissertation is to reexamine critically the characteristics of various types of interparticle interactions (van der Waals, electrostatic, magnetic, entropic, and molecular) at the nanoscale (Chapter 1). For each type, I describe the magnitude and the length scale of the interaction, its scaling with particle size and interparticle distance, and discuss the consequences for self-assembly at the nanoscale. The subsequent chapters apply these concepts and specific interaction types to guide the self-assembly of nanoparticles into 2- and 3-dimensional architectures ranging from "nanomolecules" comprised of only few particles all the way to macroscopic, nanostructured materials. Briefly, Chapters 2-6 discuss the fundamentals and often peculiar behaviors of charge nanoparticles as well as their use in assembling ionic-like superlattices and robust surface coatings. In Chapters 7-8, I described how light can be used to induce the self-assembly of nanoparticles into ordered crystals or plastic, macroscopic metals through molecular dipolar interactions Finally, Chapter 9 describes a new approach to building finite-size "nanomolecules" using the chemical concept of steric hindrance at the nanoscale. Overall, it is my hope that this Dissertation will provide a resource - easily accessible to a general nanoscience audience - of nanoscale-specific interparticle forces that can be implemented in models or simulations of self-assembly processes at this scale. |
