Biodegradable cellular polylactic acid ferroelectrets with strong longitudinal and transverse piezoelectricity

Abstract

Polymers with electrically charged internal air cavities (ferroelectrets) reveal a pronounced piezoelectric response and are regarded as soft electroactive multi-functional materials. This work presents preliminary results on the preparation and piezoelectric effect of ferroelectrets based on the polylactic acid (PLA) polymer. A distinctive feature of the manufactured films is that they are biodegradable. After a microstructure modification of carbon dioxide (CO2) foamed PLA sheets by hot-pressing treatment and corona polarization, these cellular films reveal large piezoelectric d33 and d31 responses in both quasi-static and dynamic modes. For freshly charged films, the maximum quasi-static piezoelectric coefficients are about 600 pC/N (d33) and 44 pC/N (d31) for a relatively thick film of 360 μm and a nominal porosity of about 60%. During the first 20 days after polarization, the piezoelectric activity decreases by half compared to the primary value, but then remains almost unchanged for a long time. Due to an already established inherent biocompatibility of PLA polymers, these eco-friendly ferroelectrets can be potentially used in various biological applications such as biosensors and microenergy harvesters embedded in tissue and artificial muscles.

Piezoelectric Polymeric Foams as Flexible Energy Harvesters: A Review

“…Polylactic Acid (PLA)-Based Piezoelectrets: Recently in 2020, Zhukov et al [96] prepared new biodegradable cellular piezoelectret films of PLA and presented the preliminary measured outcomes of both its fabrication and piezoelectricity measurements. They followed the classical method for piezoelectret preparation such as microstructure alteration using CO 2 -hot pressing-corona charging.…”

“…Reproduced with permission. [96] Copyright 2020, AIP Publishing. ) denotes the performance level of the COC piezoelectrets reported from past literature.…”

Ferroelectret energy harvesting with 3D‐printed air‐spaced cantilever design

“…[15][16][17] Other polymer categories that can be considered piezoelectric are the voided charged polymers, also called ferroelectrets or piezoelectrets. [18][19][20][21] In this paper the expression ferroelectrets will be used. The early ferroelectrets were polarized cellular polymers, foremost polypropylene (PP), exhibiting high piezoelectric activity that exceeds PVDF.…”

Highly Efficient Piezoelectrets through Ultra-Soft Elastomeric Spacers

“…Depending on the pore structure, ferroelectrets can be divided into three groups: (a) ferroelectrets with a closed pore structure and lens-like air voids [9,[12][13][14][15][16], (b) multilayer configurations with open-porous foams embedded between two thin, solid polymer films [17][18][19][20][21][22][23], and (c) polymer arrays with artificially introduced air voids [24][25][26][27][28][29][30][31]. All of the above structures are originally non-polar and must be polarized in a sufficiently large external electric field to exhibit piezoelectricity.…”