Nanotechnology can be described as a science, engineering and technology that is conducted at a nano scale. It involves manipulation of individual matter at the level of atoms (atomic level), molecular and or supramolecular level. It deals with materials having at least one spatial dimension in the size range of 1 to 100 nm. What comes to your mind whenever you hear the word nano is 10-9 and one nanometer is one billionth of a meter. In order to work at the atomic level one needs a suitable microscope such a scanning tunneling microscope (STM) and atomic force microscope (AFM). Nanotechnology is an interdisciplinary and also referred to as general purpose technology.
The term nano came from the Greek word nanos meaning 'dwarf’; consequently, very small objects come to the mind when we hear the word nanotechnology. Although human exposure to nanoparticles has occurred throughout human history which dramatically increased during the industrial revolution. The study of nanoparticles is not new as the concept of ‘‘nanometer’’ was first proposed by Richard Zsigmondy in 1925; a Nobel Prize Laureate in chemistry who coined the term expressly for characterizing particle size and he was the first to measure the size of particles such as gold colloids using a nanometer. However, Richard Feynman, the 1965 Nobel Prize Laureate in physics is often credited for introducing the concept of nanotechnology and therefore called the father of nanotechnology. He presented a lecture titled "There's Plenty of Room at the Bottom" where he introduced the concept of manipulation at the atomic level. The new idea he presented demonstrated new ways of thinking and his hypotheses were proven correct.
Fifteen years later, a Japanese scientist named Norio Taniguchi was the first to use the word nanotechnology to describe semiconductor processes that occurred on the order of nanometer and advocated that nanotechnology consisted of the processing, separation, consolidation, and deformation of materials by one atom or one molecule. Thereafter, the golden era of nanotechnology began in the 1980s when Eric Drexler of Massachusetts Institute of Technology (MIT) used ideas from Feynman’s book and Taniguchi’s term nanotechnology in his book titled, ‘‘Engines of Creation: The Coming Era of Nanotechnology’’ in 1986; he proposed the idea of a nanoscale ‘‘assembler’’ which would be able to build a copy of itself and of other items of arbitrary complexity. His vision of nanotechnology is often called ‘‘molecular nanotechnology.’’
Nanotechnology's advancement became popular when Iijima and another Japanese scientist, developed carbon nanotubes; the beginning of the 21st century saw an increased interest in the emerging fields of nanoscience and nanotechnology. In the United States, Feynman’s stature and his concept of manipulation of matter at the atomic level played an important role in shaping national science priorities. President Bill Clinton advocated for funding of research in this emerging technology during a speech at Caltech on January 21, 2000. Three years later, President George W. Bush signed into law the 21st Century Nanotechnology Research and Development Act. The legislation made nanotechnology research a national priority and created the National Technology Initiative (NNI). Today, the NNI is managed within a framework at the top of which is the President’s Cabinet-level National Science and Technology Council (NSTC) and its Committee on Technology. The Committee’s Subcommittee on Nanoscale Science, Engineering, and Technology (NSET) is responsible for planning, budgeting, implementation, and review of the NNI and is comprised of representatives from 20 US departments and independent agencies and commissions.
Approaches in Nanotechnology: Synthesis of Nanomaterials
There are two approaches to the synthesis of nanomaterials: bottom-up and top-down. The bottom-up approach involves molecular components arranging themselves into more complex assemblies atom-by-atom, molecule-by-molecule, cluster-by-cluster from the bottom as in the growth of a crystal. These approaches, arrange molecular components themselves into some useful conformation using the concept of molecular self-assembly; synthesis of nanoparticles by colloid dispersions is an example of the bottom-up approach.
In the top-down approach, it has to do with creating nanoscale devices by using larger, externally-controlled devices to direct their assembly; this approach often uses the traditional workshop or microfabrication methods in which externally-controlled tools are used to cut, mill and shape materials into the desired shape and order. Attrition and milling for making nanoparticles are typical top-down processes.
The structure of the nanomaterials can be classified by their dimensions. The zero-dimensional nanostructures are nanoparticles. The one-dimensional nanostructures are whiskers, fibers (or fibrils), nanowires and nanorods. In many cases, nanocables and nanotubes are also considered one-dimensional structures. Thin films are considered as two-dimensional nanostructures. Colloids bearing complex shapes have three-dimensional nanostructures.
Nanotechnology has been applied in many sectors around the world; current applications of nanoscale products in consumer products around the world include:
1. Automotive: production of air and oil filters, waxes, engine oil, anti-scratch finishes, car wax, air purifiers, catalysts to improve fuel consumption, tires.
2. Clothing and Textiles: wrinkle and stain resistant apparel, antibacterial and anti-odour clothing, antibacterial fabrics, UV resistant and protective clothing, flame retardant fabrics.
3. Cosmetics: skin cream and moisturizers, skin cleansers, sunscreen, make up removal.
4. Electronics: batteries, electronic displays; organic light emitting diodes (OLED and LEDs), data memory, antibacterial and anti-static coatings on keyboards, mouse, cell phones, DVD coatings, mp3 players, computer processors and chips.
5. Food, Food Additives and Food Packaging: energy drinks, nutritional supplements, food storage containers, antibacterial utensils, cutting board, plastic wrap, food packaging, nano tea, chocolate shakes, canola active oils.
6. Household: antibacterial furniture and mattresses, antibacterial coatings in appliances, filters, air purifiers, self-cleaning glass, antibacterial, UV resistant paints, vacuums, solar cells, cleaning products, disinfectant sprays, fabric softeners.
7. Health/Personal Care: hearing aids, body wash, contact lenses, cellulite treatment, tooth powder, shampoos, hair gel, deodorants, insect repellents, antibacterial creams, bandages, home pregnancy tests, drug delivery patches, man made skin.
8. Sport Equipment: gulf balls and club, tennis racket and balls, base ball bats, hockey sticks, skis and snowboards, ski wax, bicycle parts, wet suits, shoe insoles, anti-fogging coats.
9. Toys and Children's Goods: stain resistant plush toys, antibacterial baby pacifiers, mugs and bottles, X-boxes and PlayStation, antibacterial stuffed toys.
10. Medical Application: drugs, medical devices
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