The focus of this book is to explore and discuss in detail the fabrication of various polymer nanocomposites, such as thermoplastic polyurethane (TPU), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVDF), Spandex rubber, and polylactic acid (PLA) in the composition of varieties electroconductive particles mainly, graphene, CNT (carbon nanotube), nano CF (carbon fiber) fiber, nano conductive fiber, and ionic liquid (IL) for pressure sensing applications. A general description of PVDF, TPU, Spandex rubber, and PLA has been described in short for their physical properties, chemical structures, and their area of applications. Consequently, we optimally estimated and established an experimental route for successive preparation of micrometer (mim) thick and flexible nanofiber webs having fiber dia at the nanometer (nm) scale, for the fabrication of a piezo resistive, piezo capacitive, and piezoelectric pressure-based sensors.