**1.3 Physical properties of nanodielectric-based polyimide**

For the last decade, the research has shown that when two materials in which one part is inorganic nanoparticles are combined to form a nanodielectric material, which *Synthesis Process Optimization of Polyimide Nanocomposite Multilayer Films, Their Dielectric… DOI: http://dx.doi.org/10.5772/intechopen.91206*

may have superior properties than single ones. The combined nanodielectric materials are known as polymer nanocomposites, when the base material is polymer matrix and the adding fillers are nanoparticles. Polymer nanocomposites have been used widely in academic research and industry [13]. The properties of nanocomposites change due to the large surface to volume ratio of the nanoparticles. The addition of nanoparticles into the base polymer matrix modifies the physical properties of composites. If the size of the nanoparticles is less than the critical length scale, then the physics of nanocomposite changes significantly. It has become one of the most reliable materials in electrical engineering since the first time the term nanocomposite was introduced in 1984 and since then it has been warmly accepted by the scientific community [13]. "Nanometric dielectrics," later named "Nanodielectrics" in 2004 by M.F. Frechette, is a nowadays popular term in the research community also known as nanocomposites made by the inclusion of nanometer size of nanoparticles in a polymeric matrix for dielectric applications [13]. In the beginning, the glass and ceramics were very common to use as solid dielectric materials. But, over time the power supplies demand increased abruptly, and these insulating materials were not enough to fulfill the demand. Therefore, new dielectric materials such as natural and synthetic polymers successfully overcome conventional dielectric materials. These new polymer-based dielectric materials have superior properties and lighter in weight to use in different applications.
