The structural metamaterials have properties of light weight and crushability. Such materials can withstand a load of at least 160,000 times their own weight by over-constraining the materials.  \cite{gizmag}

The properties of this metamaterial change with the power of incident waves. The nonlinear metamaterials have much stronger ability in including the local electromagnetic fields. This metamaterial is important to non-linear optics. 

The realization of traditional  Electromagnetic stealth is to apply material that can absorb electromagnetic waves to object, in that way the object is hard to be detected. However, the limitation of this method is that it only decreases the risk of being detected by radar which has specific frequency.

In 2006, Pendry and his team put forward a method that using transformation of coordinates to design metamaterials, using the different distribution of dielectric constant and permeability to control the travel path of electromagnetic and produce no scattering to realize cloaking.\cite{Pendry_2006} The shape that Pendry  stipulates is sphere which has lots of limitations. However, later than that,Cummer and his team designed a cylindrical cloaking device\cite{Cummer_2006}  Ma design an arbitrary cloaking device in 2009.\cite{Hua_2009}

However, the cloaking devices are still on experimental stages, it will be far that the devices come into people's life.

Self-healing plastics uses small  molecule connection or makes a "bridge" on the plastic chemical object to make a form of a long chain. When the plastic break, these connection would break and change the shape. The position broken would appear red points. When the outside environment(PH, temprarure) changes, the "bridge" inside would reframe and fix the broken position itself. When the process finishes, the red point disappear.

Generally, ceramics are superior in strength to metals at high temperatures, however, they are brittle and sensitive to flaws, and this brings into question their integrity and reliability as structural materials. \cite{Ono} Mn+1AXn phase ceramics, also known as MAX Phases, can autonomously heal crack damage by an intrinsic healing mechanism.

The conductivity of a conductor is hard to reach 100%. However, stanene—— a material made of  a single atomic layer. The single atomic layer is made up with atom Sn rather than atom C. This endows the new material the unique property —— conductivity of 100%.

In 2013, Zhang in Stanford theorize the Stanene for the first time \cite{Wang_2013} According to their model,  the stanene is insulation inside and conductor outside. In that way Stanene can realize the conductor with 100% conductivity in indoor temprature.

Aerogel can be made of plenty of object, including SiO2, metallic oxide and carbon. Because the fact that the air take most of its ingredient, Aerogel is also a good insulator. Furthermore, the structure of it endows it strong tenacity.  Nowadays, the scientist in NASA has been doing an experiment of Aerogel to make it as the insulating material of aircraft when going through the atmosphere. 

Since twenty-first century, metamaterials have been a priority of scientific research. More and more kinds of metamaterials have come into appearance which bring the scientific field much convenience. The application of metamaterials is blending into people's normal life. In the lately a few years, metamaterials must still be the focus of scientific research.