Synthesis and Characterization of Advanced Carbon-Based Nanowires – Study of Composites Actuation Capabilities Containing These Nanowires as Fillers

International audienc

Effects of Zr/Ti ratio on structural, dielectric and piezoelectric properties of Mn- and (Mn, F)- doped lead zirconate titanate ceramics

International audienc

Corrigendum to “Magnetoelectric coupling in Fe3O4/P(VDF-TrFE) nanocomposites” (Sens. Actuators A 247 (2016) 298–306) (S0924424716302989)(10.1016/j.sna.2016.06.013)

The author regrets that one of the authors name “Fouad BELHOURA” has been mistaken and shall be corrected and changed to “Fouad BELHORA”.The author would like to apologise for any inconvenience caused.International audienceNanocomposite films composed of nanoparticles Fe3O4embedded in copolymers of vinylidene fluorideand trifluoroethylene P(VDF-TrFE) (70/30) have been elaborated. The effect of Fe3O4content on thecristallinity ratio, dielectric and magnetoelectric properties of the nano-piezo-composites was studiedand discussed. Dielectric characterization showed an increase of the permittivity and a decrease of theresistivity with the increasing ratio of nanofillers. Thermal analysis revealed a decrease of the cristallinityof the composite. Poling process was found to be difficult for Fe3O4contents higher than 1%, because ofthe low breakdown fields and diminished resistivity with increasing Fe3O4content. As a consequence,magnetoelectricmeasurementswereconductedonlyonnanocompositeswithFe3O4contentslowerthan0.5% in the case of poled samples. The optimal value of the first order magnetoelectric (ME) coefficient ̨pwas obtained for a nanoparticles content of 0.3% wt

Temperature dependence of piezoelectric properties of PMN-PT and PZN-PT single crystals

The temperature dependence of the piezoelectric properties of 0.67Pb (Mg$_{1 / 3}$Nb$_{2 / 3})$O$_{3}$-0.33PbTiO$_{3}$ and 0.955Pb(Mg$_{1 / 3}$Nb$_{2 / 3})$O$_{3}$-0.045PbTiO$_{3}$ single crystals, respectively grown by Bridgman and modified Bridgman method was investigated. Due to their low rhombohedral to tetragonal transition temperature and Curie point (T$_{\rm c}$ = 152$^{\rm o}$C and 166$^{\rm o}$C), the properties of these single crystals have an unstable behavior as soon as the first transition temperature is reached, i.e. the piezoelectric coefficients exhibit a non linear or a hysteretic behavior during temperature cycle.
The objective of this paper is to study the thermal stability of piezoelectric and dielectric coefficients for the two compositions in order to point out the limiting factors in term of transducers performances and to explain the observed behavior

Thickness-dependent microstructural and electromechanical properties in polyurethane films obtained by polymer solution casting

International audienceElectroactive polymers (EAPs) are promising materials for actuation and energy harvesting applications. Among the EAPs, polyurethane (PU) material is of considerable interest given its high values of deformation under an electric field. The electromechanical properties were found to be dependent on the processing technique and the thickness of the film. To understand this relationship, a comprehensive study was carried out on polyether-based thermoplastic PU elastomer films elaborated by solution casting with thicknesses between 12 and 220 μm. Microstructural, dielectric, mechanical, and electrostriction studies were conducted. Thin films present a lower strain for a given electric field compared to thick films. The films exhibit a structural gradient along the thickness direction: a fast evaporation in the upper part of the film close to the interface with air inhibits the phase separation but a more favored one in the lower part. This is consistent with the modeling based on the gradient of dielectric constant and the experimental, mechanical, and dielectric characterizations