Abstract: A process for producing an ultrafine metal particle/polymer hybrid material (inorganic/organic hybrid material or functional polymeric material) from a polymer and ultrafine metal particles (nanoparticles of a metal). The hybrid material is applicable in various fields of nanotechnology, can be in various forms (solution, gel, and thin film), and performs specific functions. The invention further relates to explications and interpretations of the mechanism of its formation and the structure and properties (functions, behaviors, phenomena, etc.). It furthermore relates to the fact that the process for producing an ultrafine metal particle/polymer hybrid material and the explications and interpretations of the mechanism of its formation and of the structure and properties thereof apply not only under gravity but also microgravity and non-gravity.