Modifications induced in PVDF films by irradiation with energetic heavy ion beam have been determined by electron spin resonance (ESR). We have studied the evolution of radical density under different measurements atmospheres (vacuum and air) as function of temperature, ageing time and annealing. The dynamic of pore formation has been studied using a conductivity cell. The evolution of track and bulk etching rates has been determined as function of the solution temperature and of the reactive concentration.