Polymer nanocomposites, nanoparticle-containing organogels utilized in forming the polymer nanocomposites, and methods for forming the polymer nanocomposites and nanoparticle-containing organogels are disclosed. Relatively simple and versatile methods are utilized to form the polymer nanocomposites. The process is based on the format of a three-dimensional network of well-individualized nanoparticles, such nanofibers through gelation thereof with an appropriate non-polymeric solvent. The nanoparticle-containing organogel is subsequently filled with a solution of a desired matrix polymer, the composite is dried and compacted to create the polymer nanocomposite. Polymer nanocomposites can be prepared which exhibit dramatic changes in mechanical properties, such as increased shear modulus, when compared to the neat polymer.