Micro-structured PDMS piezoelectric enhancement through charging conditions

Abstract

Micro-structured cellular polydimethylsiloxane (PDMS) materials were prepared by a low-cost molding process allowing us to control geometry and sample size. Cellular structures are charged with a triangular quasi-static voltage with amplitudes between 1 kV and 4 kV and a frequency of 0.5 Hz fixed after having evaluated the conditions enhancing the piezoelectric response of the cellular PDMS. The piezo-electret PDMS material charged at room temperature has a piezoelectric coefficient d 33 of 350 pC/N, which is ten times larger than that of polyvinylidene fluoride. The high piezoelectric coefficient with a very low elastic modulus of 300 kPa makes these materials very useful for wearable device applications. The piezoelectric coefficient d 33 of the samples poled at high temperatures improves thermal stability but reduces PDMS piezoelectret piezoelectricity, which is explained by the structure's stiffness. These results are useful and allow us to set the conditions for the preparation of the piezo-electret materials according to desired applications.

Piezoelectric Polymer and Paper Substrates: A Review

“…Figure 5 describes the possible combination of connectivity patterns of piezo composites in practice [ 37 ]. A low cost molding process was used by Lee et al to develop a micro structured PDMS which displayed high of 350 pC/N [ 38 ]. Woongchul et al made thin films of BaTiO and PVDF by solution casting [ 39 ].…”

“…Recently, VCPs are reported using PEN (Poly ethylene napthalate) films with diffusion of CO gas to form voids [ 44 ]. Molded PDMS based VCPs are also reported [ 38 ].…”

Thermal Stability of Micro-Structured PDMS Piezo-Electrets under Various Polymeric Reticulation Ratios for Sensor Applications

“…According to Figure 2, the highest longitudinal piezoelectric coefficient is identified for the 1:20 ratio PDMS piezo-electret material (d33 = 750 pC/N) at 25 °C. This is mainly due to the lower Young's modulus of this material as reported in our previous work [4]. However, this ratio presents the lowest thermal stability as the piezoelectricity is lost at 45 °C.…”

“…However, the flexibility obtained with such materials was limited. In recent years, another family of piezoelectric polymer materials has appeared and seems to constitute good candidates as a compromise combining flexibility and significant piezoelectric effect [4]. These so-called piezo-electrets are heterogeneous materials exhibiting a piezoelectric behavior with thicknesses varying from few dozen to few hundred microns.…”

Optimization a structure of MEMS based PDMS ferroelectret for human body energy harvesting and sensing

“…The demonstrated piezoelectric coefficient d 33 was 182 pC N −1 , for the pure PDMS structure, which was about 40% smaller than the PP foam ferroelectret. A similar mouldcasting approach fabricated PDMS ferroelectret with circular voids with a diameter of 100 μm and height of 40 μm [17]. The d 33 of the fabricated ferroelectret was 350 pC N −1 .…”