Nanomaterials: A History and Principles of Synthesis PDF

# Nanomaterials: A History and the Principles of Synthesis ## Introduction Nanomaterials have existed for centuries. This document will discuss the history of nanomaterials and the principles involved in synthesizing them. * **Surface atoms/volume ratio**: For nanomaterials, the surface...

# Nanomaterials: A History and the Principles of Synthesis ## Introduction Nanomaterials have existed for centuries. This document will discuss the history of nanomaterials and the principles involved in synthesizing them. * **Surface atoms/volume ratio**: For nanomaterials, the surface-to-volume ratio is very high. This ratio means that there are a large number of surface atoms compared to the total number of atoms in the material. ## The History of Nanomaterials * **Ancient Romans**: The Romans used nanomaterials in glassmaking. The Lycurgus Cup, made in the 4th century, is a famous example. This cup appears green in daylight but red under transmitted light due to the nanoparticles of gold and silver that are embedded in the glass. * **Medieval Times**: In the 6th to 15th centuries, gold and silver nanoparticles were used to create stained-glass windows in cathedrals. The colorful hues were achieved by manipulating the material's plasmon excitation. * **19th Century**: Michael Faraday first described colloidal gold in 1857. He noted this material's unique optical and electrical properties. However, the ability to characterize and manipulate nanomaterials at the atomic level was restricted due to the limitations of microscopy at the time. * **Late 20th Century**: The invention of the scanning tunneling microscope (STM) by Gerd Binnig and Heinrich Rohrer in 1981 revolutionized the study of nanomaterials. STM could visualize surfaces at the atomic level and led to significant breakthroughs in nanoscience and nanotechnology. The atomic force microscope (AFM), also invented in the 1980s, allowed scientists to study non-conductive materials at the nanometer scale. * **21st Century**: The National Nanotechnology Initiative, a federally funded research and development program in the United States, was launched in 1999. The goal of the initiative was to promote the development of nanomaterials and the application of nanotechnology in various fields such as medicine, electronics, and energy. ## Principles of Nanomaterials Synthesis * **Size and Shape Control**: In the synthesis of nanomaterials, controlling the size and shape is essential. The properties of nanomaterials are highly size and shape dependent. The size of the nanoparticle determines its surface-to-volume ratio, which is critical for applications such as drug delivery or catalysis. It is also important to control the shape of the nanoparticle, as this impacts its surface area, reactivity, and overall properties. * **Shape Control**: Nanomaterials can be synthesized in various shapes, including spheres, rods, wires, and tubes. The shape of the nanoparticle is determined by a variety of factors, such as the synthesis method, the reaction conditions, and the presence of surfactants. ## Examples of Nanomaterials * **Fullerenes (Buckyballs)**: These spherical molecules, discovered in 1985, consist of 60 carbon atoms arranged in a closed, shell-like structure that resembles a soccer ball. Fullerenes have remarkable properties that include high strength, low density, and excellent electrical conductivity. * **Carbon Nanotubes**: Discovered in 1991, carbon nanotubes are cylindrical structures made of one or more layers of graphene rolled into a tube. Carbon nanotubes are extremely strong, light, and have excellent electrical and thermal conductivity. ## The Importance of Nanomaterials Nanomaterials hold great promise for a wide variety of applications, including: * **Medicine**: Nanomaterial particles can be used to deliver drugs, genes, and other therapeutic agents to specific locations in the body. * **Electronics**: Nanomaterials are used in applications such as transistors, solar cells, and sensors. * **Energy**: Nanomaterials are used to improve the efficiency of batteries, fuel cells, and solar cells. The future of nanotechnology is exciting. As research in this field continues, we can expect to see even more innovations that benefit society.