Piezoelectric membranes were produced by "poling" prefabricated polyvinylidene fluoride (PVDF) membranes in an electric field. Scanning electron microscopy (SEM) studies revealed that electrical poling changed the microstructure of membranes significantly. Infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) measurements confirmed the formation of beta-phase crystals in PVDF membranes as a result of poling in an intense electric field. Dynamic mechanical analysis (DMA) and measurement the surface displacement when the membranes were energized by AC signals, confirmed that the poled membranes were piezoelectric. Piezo-response force microscopy (PFM) analysis showed that the piezoelectric domains were not uniformly distributed over the sample. (C) 2013 Elsevier B.V. All rights reserved.