As I have already discussed the optical and electrical properties of nanomaterials, today I will discuss the mechanical properties of nanomaterials. Mechanical properties like physical properties like strength, melting point etc. also shows drastic change at nano scale level. Let us discuss the example of this:
1.) Bulk level steel is highly stronger than carbon (graphite) but at nanoscale cylinders of carbon are 100 times stronger than steel and very flexible.
2.) Melting point goes on decreasing with decrease in size. Let us discus the reason:
The melting point as a layman definition is the temperature at which a material melts. According to the microscopic definition of a substance, it is defined as the temperature at which molecules in it posses just enough energy to overcome intermolecular forces that hold them in a fixed position in a solid. Atoms on the surface of a substance require less energy to move because these are in contact with lesser number of atoms of substance. While atoms inside the bulk of sample are surrounded by large number of atoms and require more energy to move. Therefore at macroscale level if size of sample is changed then percentage change in the number of atoms in size at macroscopic level. However at nanoscale level if size of object is changed then percentage change in number of atoms on the surface is very large.
Due to this melting point starts depending on the size of object and melting point goes on decreasing with decrease in size.
Note: If you know more mechanical properties of nanomaterials then please share with us.