ABSTRACT
Intuitively, it is clear that nanotechnology deals with very small objects and such small objects were called "nano-objects" earlier. Nano-objects are material samples having sizes of about 1 to 100 nm. In this chapter, the principal object of discussion is electrospun polymer nanofibers, and despite the fact that the diameters of these nanofibers can exceed a few hundreds nanometers and even micrometers. In order to better understand what "nano-objects" mean, the chapter discusses their intrinsic physical properties and explains the features of nanoscale objects from the physical point of view. Mechanical properties of polymers depend on their molecular weight, crystallinity and conformational state. The chapter discusses only macroscopic properties of polymer materials, ignoring any details on the molecular level. Additional ideas should be utilized in order to understand the observed size-dependent behavior. One of such ideas is the confinement concept, which explains the size-dependent behavior by geometrical restrictions.
