Energy absorption capacity of ferroelectrets based on porous polypropylene

Abstract

Ferroelectret materials are special group of piezoelectric materials obtained from the cellular structure of nonpolar polymers. They are under investigation for a variety of applications such as actuators, vibration control, speakers, microphones, sensors, as well as healthcare monitoring systems. In this work, the effect of morphological and mechanical properties of ferroelectret films on their capacitance and stored energy capacity was studied. Different eye‐like cellular structure of porous polypropylene films with different cell aspect ratio (AR) and mechanical properties were used. The optimized sample was obtained with AR = 6.6 using nitrogen (N2) as the ionizing gas to give a quasi‐static piezoelectric coefficient (d33) of about 800 pC/N, an electrode charge density of about 2.10 mC/m2, a maximum capacitance of about 465 pF, as well as a maximum stored energy capacity of about 1,824 pJ. It was observed that replacing air with N2 as the ionizing gas led to an increase in charge/voltage output. Moreover, by replacing air with N2 as the ionizing gas, the capacitance and stored energy of the samples were improved by about 20% and 80%, respectively. Hence, it can be concluded that the capacitance was mostly related to the cellular morphology of the samples while the stored energy was also function of the ionizing gas used. POLYM. ENG. SCI., 58:300–309, 2018. © 2017 Society of Plastics Engineers

Piezoelectric Polymeric Foams as Flexible Energy Harvesters: A Review

“…Mohebbi and Rodrigue (2018) [48] PP 800 -%1,824 pJ When the air was replaced with N 2 , an improvement of 20% and 80% in the capacitance and stored energy of the samples, respectively, was noted.…”

“…They reported the d 33 coefficients 800 and 550 pC N −1 for treated and untreated samples, respectively. In 2018, Mohebbi and Rodrigue [ 48 ] optimized a cellular PP film with AR of 6.6 using N 2 (ionizing medium) and measured d 33 of ≈800 pC N −1 . The electrode charge density was ≈2.10 mC m −2 , capacitance ≈465 pF, and higher stored energy ≈1,824 pJ.…”

Gas transport properties of cellular hollow fiber membranes based on LLDPE/LDPE blends

“…10,12 Melt processing can be done by stretching and melt spinning of semi-crystalline thermoplastics such as polypropylene (PP). 13 But this method requires several mechanical stretching and thermal post-treatment to stabilize the crystalline and porous structure to prevent membrane shrinkage. 14 Another non-solvent technique is to use leachable particles (salts) to prepare a composite leading to an open-cell structure.…”

Dielectric and mechanical optimization properties of porous poly(ethylene‐co‐vinyl acetate) copolymer films for pseudo‐piezoelectric effect

“…The artificially embedded dipoles could respond to an external applied electrical field or mechanical stress/strains force, similarly to any piezoelectric materials [31][32][33][34]. Instead of charge displacement in a crystalline structure of a regular piezoelectric material, the effect called pseudo-piezoelectric effect in charged polymer foams arises from the deformation of the ionized cells [35][36][37][38][39]. As mentioned later, giant pseudo-piezoelectric constants are obtained for a charged porous polymer with low dielectric constants compared to conventional piezoelectric polymers and ceramics [40][41][42][43][44][45][46][47].…”