2014 We study the behaviour of piezoelectricity in highly heterogeneous media. The piezoelectric effect introduces a coupling between electrical and mechanical properties, which have separately different scaling behaviours. Its study therefore constitutes a priori an interesting question. This problem is also suggested by the recent development of low-density, porous piezoelectric ceramics whic...

Based on the energy-minimization method in molecular simulation, the origin of piezoelectricity in b-phase PVDF crystals was investigated. Simulation results indicated that under the action of a constant applied voltage, PVDF crystal would be stretched or compressed, dependent on the orientation of dipoles and the polarity of the applied voltage. Our simulation confirmed that piezoelectricity i...

Interferometric measurements of bovine bone and tendon show that the values of the piezoelectric strain constant d14 decrease with hydration from the dry values of 0.2 X 10(-14) and 2.0 X 10(-14) m/V, respectively. The decrease of piezoelectricity in tendon is exponential with a characteristic hydration of 7% by weight from which an upper limit of the average molecular weight of the responsible...

The effect of the polymeric reticulation on the thermal stability of the piezoelectricity of a micro-structured PDMS piezo-electret was investigated. This new family of flexible piezoelectric materials with very low Young’s modulus is used for wearable sensors and energy harvester devices. The best thermal stability was obtained for the piezo-electret material made from the ratio 1:10 between t...

We consider theoretically the properties of piezoelectricity in cholesteric elastomers. We deduce using symmetry considerations the piezoelectric contributions to the free energy in the context of a coarse-grained description of the material. In contrast to previous work we find that compressions or elongations of the material along the pitch axis do not produce a piezoelectric response, in agr...

Dentin is a mesenchymal tissue, and, as such, is based on a collagenous matrix that is reinforced by apatite mineral. Collagen fibrils show piezoelectricity, a phenomenon that is used by piezoresponse force microscopy (PFM) to obtain high-resolution images. We applied PFM to image human dentin with 10-nm resolution, and to test the hypothesis that zones of piezoactivity, indicating the presence...