Hybrid materials combining metallic nanoparticles (NPs) and polymers has stimulated a large effort to make new optical, electronic and magnetic [1, 3] properties emerging. Such composite nanomaterials have the potential of improving the functionality of devices ranging from information storage to microelectronic sensors [4,5]. In this context, hybrid nanomaterials combining platinum (Pt) nanoparticles (NPs) and poly(?-benzyl-L-glutamate) (PBLG) in alpha helice conformation were investigated by in situ alternative-current impedance spectroscopy as a function of temperature, applied DC bias voltages and PBLG polymerization degree. TEM images of the hybrid materials show a lamellar structure, made possible by Pt, whose organization depends on the degree of polymerization. The corresponding Nyquist?s plots generated from the impedance spectroscopy data show that for each degree of polymerization, a perfect semi-circle typical of an equivalent electrical circuit consisting of parallel resistance R and capacitance C plus a series resistance Rs is observed. The R and C values are obtained using a fitting procedure. This procedure allows determining the relaxation time constant, which is interpreted as the characteristic time of a dipolar relaxation process. Variations of ? with temperature are well described by Arrhenius's law which allows to extract the activation energy of the relaxation process. We found that the activation energy is around 0.1 eV whatever the DP of the PBLG. It is comparable to the stretching vibration energy of the CN bond in PBLG, which is in favor of a conduction process involving polaronic coupling and hopping. The evolution of the activation energy with applied DC Bias voltage and the polymerization degree reveals a piezo-electric effect induced by the presence of the Pt NPs. This piezo-electric effect is not present in the pure PBLG reference sample and is due to the orientation of the dipoles carried by the ? helice and to the lamellar structure of the hybrid Pt-PBLG nanomaterial. We will discuss the obtained results and show that impedance spectroscopy under applied DC bias is able to address the physics of dipole relaxation and charge carrier dynamics in polymer/nanoparticle nanostructured hybrid materials.