Nanotechnology is manufacturing on the tiniest of scales. The mastery of tools is the crowning achievement that distinguishes humans from most other animals. Therefore, nanotechnology would be considered the ultimate tools.
For the topic of using carbon nanotubes to replace silicon, see Quantum Computers.
In the 1990s, scientists at NASA discovered a new material: carbon nanotubes. The strong bonds between the carbon atoms make it stronger than steel and 1/6 the weight. When they were discovered, they immediately went into industry. But they did not enter the mainstream until World War III. During World War III, the USA started the Geronimo Program to develop new weapons and defenses. One of the early projects of the Geronimo Program was to develop a new suit of armor based on carbon nanotubes to replace Kevlar. Experts on carbon nanotubes provided the necessary knowledge to create long enough carbon nanotubes to create it. The result was a suit of armor that was so light only one sheet was needed to deflect a bullet which could not even penetrate. Jurisdiction of this project was transferred to the military afterwards.
Years later, the specifications for Geronimo III included transistors made of carbon nanotubes. Coupled with a neural net, these transistors created automated tanks that were effective against those of the Holy Islamic Caliphate. Carbon nanotube transistors would become one many replacements for silicon transistors for years before the quantum computer entered the mainstream.
After World War III, modular robots were used to repair the ruined infrastructure of the planet. They did it using carbon nanotubes created inside nanotube factories located inside the robots. It was through this that Third Holy Temple in Jerusalem, Israel was constructed. It was also through this that the first space elevator was constructed. However, the carbon nanotube was not the only nanomaterial used.
For the topic of using graphene to replace silicon in computers, see Quantum Computers.
In 2004, Andre Geim and Kostya Novoselov isolated graphene from graphite. Graphene is essentially an un-rolled carbon nanotube. Because of its highly conductive properties, graphene was used to make ultracapacitors for electric cars. Graphene was also used to create more efficient solar panels. But the most important application came during World War III.
During World War III, Geronimo III developed automated tanks to counter those of the Holy Islamic Caliphate. Aside from the carbon nanotube transistors, these robo-tanks were required to have a complement of graphene transistors which added computer power. Both types of transistors were commonplace after World War III until quantum computers entered the mainstream. But graphene could do more than create a more powerful transistor. It also served as the main hull material for the robo-tanks. Thus, the robo-tanks could get bigger while being protected from enemy fire.
Nanomaterials were the key to the development of nanotechnology. They allowed sensors to be miniaturized, for example.
See also: Genetic Engineering
The DNA chip is a miniature medical tricorder. Embedded in it are DNA fragments, miniaturized sensors, and a laser used to identify thousands of genes. Medical analysis is possible within minutes. DNA Chips were incorporated into the bathrooms of most people. They also went into clothes and, even, into the bodies of people themselves. They went through the blood vessels most people detecting genetic mutations. They even delivered medicine where it was needed when incorporated into smart pills, nanoparticles, and, even, nanocars.
During World War III, nanomachines with DNA chips were used to cure disease. They were used to kill cancer cells. Nanomachines also performed surgery. The success of the use of nanomachines with DNA chips meant that they were even used to eliminate genetic mutations that cause disease. If the DNA chip inside detected such a mutation, then the nanomachine would immediately get rid of it.
After World War III, some people even used nanomachines with DNA chips to alter their own appearance to resemble something out of a movie. Nanomachines with DNA chips were capable of doing that although it was controversial. Also after World War III, nanotechnology found other uses.
See also: Artificial Intelligence
Although, the technology is not mentioned in Terminator 2, the T-1000 is made of programmable matter. Programmable matter is the holy grail of modular robots. It can change shape, color, and physical form with ease. Surprisingly, the first manufacturer of catoms, the building blocks of programmable matter, was Intel. Early catoms were cylinders which worked in two dimensions, but as time went on, later catoms were spheres which worked in three dimensions. It was then that programmable matter really took off.
After World War III, many people started using programmable matter for pretty much everything. Something could be turned onto something else. Entire cities could rise at the push of a button. Bound together by nano-velcro with atomic forces, the catoms could arrange into anything useful for the time. Such programmable matter could even take on human form. So something like the T-1000 did take-off.
However, nanotechnology would do more than programmable matter. It would change the world.
By the end of the 21st century, nanotechnology would bringforth the replicator. The name comes from Star Trek. Like its namesake, this replicator could create anything. The main problem in the past was that a whole lot of atoms were needed to create something. The solution was to use self-replicating nanobots capable of identifying molecules, cutting them, and reassembling the atoms using a process called self-assembly.
The replicator proved to be one of humanity's holy s%&$^#^*%$#^ moments. As it entered the mainstream, society was radically changed. Suppliers which supplied the stuff needed to make large-scale products went bankrupt. Mortgages ceased to exist. Small-scale and medium-scale production effectively ceased to exist. Capitalism ceased to function. Scarcity was eliminated. Large-scale products were much cheaper. Politics had to keep up.
In 2100, communists took over the governments of Russia and China. They intended to keep the changes the replicator made to society under control. They were quickly overthrown. This led the communists to leave Earth and form the Communist Republic of Mercury.