Study on the polarization process for piezoelectric nanofibrous layers

Selleri, Giacomo; Gino, Maria Elena; Gasperini, Leonardo; Zanoni, Michele; Gualandi, Chiara; Focarete, Maria Letizia; Fabiani, Davide

doi:10.1109/ceidp50766.2021.9705470

Cited by 7 publications

(5 citation statements)

References 8 publications

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“…The ester oil penetrates the air pores of the nanofibrous membrane and allows a substantial increase in the electric field value applied between the high-voltage and ground electrodes. The electric properties (dielectric constant and electrical conductivity) of the used FR3 natural ester were taken into account to evaluate the electric field distribution between the two phases (oil and nanofibers) of the system, as described in detail in [ 28 ]. The applied electric field was set at 20 kV/mm, and the process took place for 10 min at 130 °C.…”

Section: Methodsmentioning

confidence: 99%

Self-Sensing Soft Skin Based on Piezoelectric Nanofibers

et al. 2023

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The development of electronic skins and wearable devices is rapidly growing due to their broad application fields, such as for biomedical, health monitoring, or robotic purposes. In particular, tactile sensors based on piezoelectric polymers, which feature self-powering capability, have been widely used thanks to their flexibility and light weight. Among these, poly(vinylidenefluoride-trifluoroethylene) (PVDF-TrFE) presents enhanced piezoelectric properties, especially if manufactured in a nanofiber shape. In this work, the enhanced piezoelectric performances of PVDF-TrFE nanofibers were exploited to manufacture a flexible sensor which can be used for wearable applications or e-skin. The piezoelectric signal was collected by carbon black (CB)-based electrodes, which were added to the active layer in a sandwich-like structure. The sensor was electromechanically characterized in a frequency range between 0.25 Hz and 20 Hz—which is consistent with human activities (i.e., gait cycle or accidental bumps)—showing a sensitivity of up to 4 mV/N. The parameters of the signal acquisition circuit were tuned to enable the sensor to work at the required frequency. The proposed electrical model of the nanofibrous piezoelectric sensor was validated by the experimental results. The sensitivity of the sensor remained above 77.5% of its original value after 106 cycles of fatigue testing with a 1 kN compressive force.

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Section: Methodsmentioning

confidence: 99%

Self-Sensing Soft Skin Based on Piezoelectric Nanofibers

et al. 2023

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“…Despite the high content of β phase in PVDF-TrFE copolymers and the addition of BaTiO 3 particles in the composites, the alignment of the FE domains is crucial for a macroscale PE behavior of the foams. 43 For efficient polarization, the poling process is usually carried out at the Curie temperature (T c ) of the PE material. BaTiO 3 has a Curie temperature of 120 C, 44 very similar to that of PVDF-TrFE(20), while T c of PVDF-TrFE( 30) is significantly lower (see Table 5).…”

Section: Piezoelectric Propertiesmentioning

confidence: 99%

Piezoelectric properties of PVDF‐TrFE/BaTiO₃ composite foams with different contents of TrFE units

et al. 2023

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Piezoelectric (PE) materials play an important role in the emerging field of micro and wearable electronics. Achieving high PE response is a key feature for their use in energy harvesting and sensing systems. In this study, highly porous lightweight composite foams composed of PVDF‐TrFE (70/30 and 80/20 mol%) and different BaTiO3 content (5, 10, and 20 wt%) are prepared by thermally induced phase separation method. The PE foams were structurally and thermally examined by using Fourier‐transform infrared spectroscopy, x‐ray diffraction, differential scanning calorimetry, and thermogravimetric analysis analyses. All composite foams were characterized by high β‐phase content, while the addition of ceramic particles resulted in higher crystallinity and thermal stability of the investigated foams. Two distinct poling methods were employed due to the different molar compositions of the copolymers. The PE response was measured by the PE strain coefficient (d33) and the output current (Ip). The composite foams based on PVDF‐TrFE 70/30 mol% copolymer, having two well‐separated Curie temperatures for the organic and inorganic phases, can be polarized to achieve the contribution of both components to the PE performance, reaching the highest value of −28.3 pC N−1 and 130 nA at 10 Hz for the composite with 20 wt% BaTiO3.

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“…Therefore, the whole polarization process was carried out in an ester oil bath (FR3 natural ester, Cargill), which penetrates the air pores between the fibers, allowing higher values of poling electric field (oil electrical breakdown equal to 70 kV/mm). Moreover, such a oil was chosen as result of a deep investigation over a wide range of embedding mediums where the nanofibers can be immerged in during the poling process [12]. Indeed, in the case of DC polarization, the electric field distributes unevenly between the two phases (PVDF-TrFE nanofibers and oil) accordingly to their electrical conductivity (σ).…”

Section: B DC Polarization Processmentioning

confidence: 99%

Comparison between AC and DC polarization methods of piezoelectric nanofibrous layers

Selleri

Gasperini

Piddiu

et al. 2022

2022 IEEE 4th International Conference on Dielectrics (ICD)

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In this paper a comparison between two different polarization mechanisms of piezoelectric nanofibers of poly(vinylidenefluoride-trifluoroethylene) (PVdF-TrFE) are presented. The direct current (DC) traditional polarization method is compared with the alternate current polarization (ACP) one. The results showed a remarkable enhancement of the piezoelectric strain coefficient d33 of the nanofibrous mats when polarized with ACP if compared with DC polarization.

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Study on the polarization process for piezoelectric nanofibrous layers

Cited by 7 publications

References 8 publications

Self-Sensing Soft Skin Based on Piezoelectric Nanofibers

Self-Sensing Soft Skin Based on Piezoelectric Nanofibers

Piezoelectric properties of PVDF‐TrFE/BaTiO₃ composite foams with different contents of TrFE units

Comparison between AC and DC polarization methods of piezoelectric nanofibrous layers

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Study on the polarization process for piezoelectric nanofibrous layers

Cited by 7 publications

References 8 publications

Self-Sensing Soft Skin Based on Piezoelectric Nanofibers

Self-Sensing Soft Skin Based on Piezoelectric Nanofibers

Piezoelectric properties of PVDF‐TrFE/BaTiO3 composite foams with different contents of TrFE units

Comparison between AC and DC polarization methods of piezoelectric nanofibrous layers

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Piezoelectric properties of PVDF‐TrFE/BaTiO₃ composite foams with different contents of TrFE units