Biodegradable and Bioabsorbable Polylactic Acid Ferroelectrets with Prominent Piezoelectric Activity

Abstract

Ferroelectrets have promoted a variety of exciting flexible sensors, actuators, and microenergy harvesters. However, most ferroelectrets have been fabricated from non‐degradable petro‐based resins, and thus the recycling of these materials constitutes a big challenge. This article reports biodegradable and bioabsorbable ferroelectret films made from polylactic acid (PLA) resins for highly sensitive transducer applications, which can operate either in piezoelectric 33 or 31/32 mode. By modification of the microstructure and polarization, pronounced longitudinal and transverse piezoelectric activities are realized in a single material. For samples with a thickness of 400 µm and a bulk density of 350 kg m−3, the Young's moduli in thickness and plane direction are ranging from 0.1 to 10 MPa, respectively. After polarization in the thickness direction, quasi‐static piezoelectric d33, g33, d31 (d32), and g31 (g32) coefficients in the PLA films, up to 500 pC N−1, 40 Vm N−1, −44 pC N−1, and −3.6 Vm N−1, are achieved, respectively. The longitudinal piezoelectric coefficients of the PLA films are comparable to non‐degradable polymer ferroelectrets, while the transverse piezoelectric activity is superior, which may be attributed to the reduction of Young's moduli in the plane direction. The preparation procedure of the PLA ferroelectrets is compatible with large‐scale production lines and thus can greatly promote their applications in green electronics.

Piezoelectric Nanomaterial‐Mediated Physical Signals Regulate Cell Differentiation for Regenerative Medicine

“…[150,151] Polylactic acid (PLA) is a biodegradable biopolymer with piezoelectric properties, although these properties are relatively weak. [152] To enhance piezoelectric properties, an effective approach was taken to incorporate an inorganic piezoelectric nanomaterial called KNN into the PLA matrix to construct a piezoelectric PLA/KNN@polydopamine (PLA/KNN@PDA) composite nanofiber scaffold. [153] As the KNN@PDA mass ratio (0-50%) increases, the peak output voltage of the nanoscaffold triggered under pressure (0.5 N, 10 Hz) increased sharply, from 0.52 V to 17.9 V. The output current increased from 0.12 to 2.6 μA, and the output efficiency was significantly improved.…”

Recent advances in modified poly (lactic acid) as tissue engineering materials

“…In recent years, researchers have paid much attention to the electroconductive and piezoelectric properties and behavior of PLA-based materials for their potential to mimic bone tissues. Ferroelectrets films created from PLA can be used to prepare biosensors involved in the development and growth of cells [212]. A biphasic layered structure was synthesized from electrospun mats of piezoelectric polyvinylidene fluoride/PLA embedded in a terpolymer hydrogel of alginate/gelatin/polypyrrolegrafted-gelatin to form osteon-mimetic samples [213].…”

“…Biopiezoelectric materials, such as barium titanate/ PLA composites, mimicked the microenvironment of bone tissue successfully and guided it through regeneration [214]. Concerning the injectability of PLA-based polymers, the scientific community has found that these biomaterials can act as an aqueous reservoir to treat defect shapes in bone tissue engineering because they can be molded easily and exhibits good biodegradability, rheology, selectivity, and targeting capability [212,[215][216][217].…”

Biodegradable, Bifunctional Electro-acoustic Transducers Based on Cellular Polylactic Acid Ferroelectrets for Sustainable Flexible Electronics

“…Figure a shows a life cycle of cellular polylactic acid (PLA) ferroelectrets, illustrating an environmentally friendly closed-loop period from functional material production to the final disposal. The specific fabrication process and electromechanical properties characterization results of the PLA ferroelectrets have been announced in our previous work, − so the present paper will give a brief description and focus on the acoustic performance of the electroacoustic transducers, involving microphones (receiver) and loudspeakers (emitter). Figure b demonstrates the potential application scenarios of the acoustic sensor in a smart home.…”