The ZnO nanostructures have been widely used in different sensing applications because of their versatile properties such as large specific surface area, nontoxicity, biocompatibility, good conductivity and piezoelectricity. Objects including reductive and oxidative gases, chemical solvents, biomolecules, mass and pressure can be detected. The high sensitivity and the low detection limit have promised a widespread application of the sensors based on ZnO nanostructures in the sensor field. ZnO nanostructures introduce benefits associated with quantum confinement including reduced dark noise, increased absorption efficiency and the potential for large area and lower cost devices. High quality nanoparticles were created with a top-down wet-chemical process. As separate materials, polymers and ZnO are already considered to be important technologically. They have found several commercial applications in optoelectronics and sensors. The interaction of ZnO with polymers may provide ways of obtaining unique or enhanced optical and electronic properties in polymer nanocomposites. Thus, by doping polymers with ZnO, new applications may be realized without losing the benefits offered by polymers in terms of processing and mechanical flexibility. ZnO nanoparticles in PDMS-ZnO nanocomposite exposed to UV irradiation absorbed radiation so the polymer structure remained intact.