Carbon Materials and Technological Advances
Carbon, one of the most abundant element in nature, has the ability to be combined chemically with itself and with other elements by strong covalent bonds resulting in a variety of structures that enable the development of materials of various properties. The carbon materials can be extremely hard as diamond or graphite as easily delaminated, very dense, high strength (composite materials carbon / carbon), and therefore suitable for structural applications (aircraft and racing cars), or very porous (activated carbon); the latter being useful as adsorbents for energy storage or as a support for catalysts. They can be highly conductive (graphite) or insulating (vitreous carbon). This broad spectrum of properties is reinforced by the fact that only carbon materials are capable of operating at high temperatures in the most extreme conditions.
The carbon materials have been gathered much attention with the discovery of fullerenes and nanotubes. However, traditional carbon materials have played an important role since prehistoric times (pigment in cave paintings, a component of gunpowder, writing) and have contributed to the industrial and technological development of our society (steel).
The discovery of carbon fibers in the ’60s, with its high strength and flexibility, was a major milestone in the development of these materials. In parallel, we discover the vitreous carbon, named after filing a conchoidal fracture surface, with properties similar to glass, very hard and brittle. At the same time, the discovery of new structural forms of graphitic carbon, needle and spherules, ostensibly contributed to the development of new carbon products for very diverse applications.
The excellent biocompatibility of carbon materials, discovered in the 70s, its use in prostheses, ligaments and heart valves, among others.
In the early ’80s, the development of technology for producing blocks of high density isotropic graphite allowed its use in high temperature reactors, in devices of synthesis of semiconductor crystals and to components of electric discharge electrodes. At mid-80s, the introduction of carbon fibers in civil engineering, architectural systems (buildings, bridges) with the discovery of fullerenes.
In the 90s, was discovered nanotubes, opening a new era for carbon materials: the era of the nanostructure. It is not just the world of carbon graphite flat structures or three-dimensional type diamond, but we are now with closed structures containing pentagons of carbon atoms and carbon tubes with diameters in the nanometer scale, made of a sheet simple curved carbon atoms in hexagonal distribution. The discovery of carbon nanotubes of a single wall (single) and multiple wall, stimulated the interest of scientists and engineers in fields related to nanotechnology. At the same time, new applications of the materials of the family of graphite, such as anode materials for Li-ion battery rechargeable carbon fiber water purification, activated carbon electrodes for electric double layer supercapacitors, etc..
More recently, in 2004, was developed the isolating graphene, a flat sheet structure of an atom thick. Its exceptional electrical properties have revolutionized the field of science, finding application in electronics (ultra-fast computers, replacing the silicon), in the future construction of space elevators, personal protection systems (body armor) in the field of security etc.. In July 2008, researchers at Columbia University confirmed that this is the strongest material so far identified.
