There are many miracles in the world, and there are even many things that we can't see all our lives. Among them, graphene is a substance that is difficult for us to touch, and many people don't know what it is. Let me take you to find out!
0 1 graphene has excellent optical, electrical and mechanical properties, and has important application prospects in the fields of material science, micro-nano processing, energy, biomedicine and drug delivery, and is considered as a revolutionary material in the future.
Physicists Konstantin Novoselov and Andre Geim of the University of Manchester in England successfully separated graphene from graphite, and they jointly won the 20 10 Nobel Prize in Physics. The common methods of graphene powder production are mechanical stripping, redox and SiC epitaxial growth, and the method of thin film production is chemical vapor deposition (CVD).
Graphene is one of the materials with the highest known strength, and it also has good toughness and can be bent. The theoretical Young's modulus of graphene is 1.0 kpa, and the intrinsic tensile strength is 1.30 GPA. The reduced graphene modified by hydrogen plasma also has very good strength, and the average modulus can reach 0.25TPa, while the graphite paper composed of graphene sheets has many holes, so the graphite paper is very fragile. The functionalized graphene obtained by oxidation and the graphene made of functionalized graphene will be extremely strong and tough.
Graphene has very good thermal conductivity. The thermal conductivity of pure defect-free monolayer graphene is as high as 5300W/mK, which is the highest thermal conductivity of carbon materials so far, higher than that of single-walled carbon nanotubes (3500W/mK) and multi-walled carbon nanotubes (3000W/mK). When used as a carrier, the thermal conductivity can also reach 600 W/MK, and the ballistic thermal conductivity of graphene can reduce the lower limit of ballistic thermal conductivity per unit circumference and length of carbon nanotubes.
Graphene is similar to graphite in chemical properties. Graphene can adsorb and desorb various atoms and molecules. When these atoms or molecules are used as donors or acceptors, the concentration of graphene carriers can be changed, and graphene itself can maintain good conductivity. When other substances such as H+ and OH- are adsorbed, some derivatives will be produced, which will make the conductivity of graphene worse, but no new compounds will be produced. Therefore, graphite can be used to infer the properties of graphene. For example, the formation of graphitic alkanes is based on two-dimensional graphene, and each carbon atom adds one more hydrogen atom, so that sp2 carbon atoms in graphene become sp3 hybridization. Soluble fragments of graphene can be prepared by chemically modifying graphite in the laboratory.