Facile Fabrication of a Flexible LiNbO<sub>3</sub> Piezoelectric Sensor through Hot Pressing for Biomechanical Monitoring

Xu, Muzhen; Ke, Hua; Guan, Li; Li, Huayi; Zhang, Meining

doi:10.1021/acsami.7b10411

Cited by 39 publications

(20 citation statements)

References 56 publications

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“…Previously, human pulse waves have been measured using sensors based on different detection mechanisms, such as optics, image processing, acoustics, and pressure means, etc. Among these, active pressure sensors based on the working principles of piezoelectricity or triboelectricity are the more intuitive and sensitive method to detect pulse waves, as these sensors can accurately and directly reflect the weak vibration of the radial artery to better imitate the pulse diagnosis in TCM. Several vertical contact‐separation and single‐electrode triboelectric pressure sensors have been published to detect human motion and physiological signals, with advantages of thin, flexible, and excellent sensitivity .…”

Section: Introductionmentioning

confidence: 99%

Human Pulse Diagnosis for Medical Assessments Using a Wearable Piezoelectret Sensing System

Chu

Zhong

Liu

et al. 2018

Adv Funct Materials

177

128

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Real-time and continuous monitoring of physiological signals is essential for mobile health, which is becoming a popular tool for efficient and convenient medical services. Here, an active pulse sensing system that can detect the weak vibration patterns of the human radial artery is constructed with a sandwich-structure piezoelectret that has high equivalent piezoelectricity. The high precision and stability of the system result in possible medical assessment applications, including the capability to identify common heart problems (such as arrhythmia); the feasibility to conduct pulse palpation measurements similar to well-trained doctors in Traditional Chinese Medicine; and the possibility to measure and read blood pressure.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adfm.201803413.imitate the TCM practice for health assessments without well-trained, real doctors. Previously, human pulse waves have been measured using sensors based on different detection mechanisms, such as optics, [16,17] image processing, [15,18,19] acoustics, [20] and pressure means, [21][22][23][24][25][26][27][28][29] etc. Among these, active pressure sensors based on the working principles of piezoelectricity [21][22][23][24] or triboelectricity [7,8] are the more intuitive and sensitive method to detect pulse waves, as these sensors can accurately and directly reflect the weak vibration of the radial artery to better imitate the pulse diagnosis in TCM. Several vertical contact-separation and single-electrode triboelectric pressure sensors have been published to detect human motion and physiological signals, with advantages of thin, flexible, and excellent sensitivity. [30] However, vertical contact-separation devices are composed of two separated parts, which increases the difficulty of assembly and operation in practice. Single-electrode triboelectric sensors have been proposed to address this issue but the exposed residual charges on the sensor surface can be easily leaked. Piezoelectret is flexible, lightweight, and have large and stable equivalent piezoelectric coefficient for high sensitivity. [25] Furthermore, sensors based on piezoelectret materials can alleviate the aforementioned issues in triboelectric sensors to detect physiological signals.In this work, we use an active and flexible pulse wave sensing system based on a fluorinated ethylene propylene (FEP)/Ecoflex/FEP sandwich-structured piezoelectret for piezoelectriclike detections. [25,26,31] Several key features are accomplished from the prototype sensing systems: 1) excellent precision and stability capable of differentiating and classifying pulses from different volunteers coupled with the help of big data analyses; 2) the identification of a common heart problem (arrhythmia) from volunteers who were previously diagnosed in hospitals equipped with advanced and bulky electrocardiogram (ECG) setups; 3) the feasibility in recording and revealing the blood pressure using the pulse sensing system instead of a ...

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Section: Introductionmentioning

confidence: 99%

Human Pulse Diagnosis for Medical Assessments Using a Wearable Piezoelectret Sensing System

Chu

Zhong

Liu

et al. 2018

Adv Funct Materials

177

128

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“…Electret materials are a kind of electrically active materials that can be polarized in the electric field and then keep the polarized state for a long time . They have wide potential applications in capacitors, transducers, memory transistors, power generators, energy harvesters, electrostatic cloak, air filters, and so on . Some natural materials (e.g., wax, rosin, and resin) and inorganic ceramics [e.g., perovskite, barium titanate (BaTiO 3 , BT), and lithium niobate (LiNbO 3 , LN)] have good electret properties .…”

Section: Introductionmentioning

confidence: 99%

“…They have wide potential applications in capacitors, transducers, memory transistors, power generators, energy harvesters, electrostatic cloak, air filters, and so on . Some natural materials (e.g., wax, rosin, and resin) and inorganic ceramics [e.g., perovskite, barium titanate (BaTiO 3 , BT), and lithium niobate (LiNbO 3 , LN)] have good electret properties . However, the former has the disadvantage of low mechanical strength while the latter has the shortcoming of low mechanical toughness.…”

Section: Introductionmentioning

confidence: 99%

High‐performance poly(vinylidene fluoride)‐polyamide 11/lithium niobate nanocomposites for the applications in air filtration

Yuan

Dong

Zhao

et al. 2020

J of Applied Polymer Sci

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To overcome the fiber-spinning problem of poly(vinylidene fluoride) (PVDF) because of its high melt viscosity and rapid crystallization, polyamide 11 (PA11) with excellent melt spinning capability and good electret properties is incorporated to prepare blends by melt mixing. Their crystal structure, morphology, electrical polarization properties, and melt spinning performance are systematically characterized by various techniques. It is found that the incorporation of PA11 reduces the crystallinity of PVDF, increases its thermally stimulated discharge current, and reduces its viscosity. Therefore, the blends show much better melt spinning capability. For such blends, the addition of outstanding inorganic electret materials, lithium niobate (LiNbO 3 , LN) nanoparticles is found to further improve the materials' electret properties. Such a strategy is proved to be successful in melt spinning PVDF electrets into fine fibers, which is beneficial to their applications in air filtration and other related fields.

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“…materials such as wax, rosin, and resin; ceramics such as perovskite, barium titanate (BaTiO 3 , BT), lithium niobate (LiNbO 3 , LN), and lead zirconium titanate (PZT); and polymers such as polypropylene (PP), nylon (PA), and poly(vinylidene fluoride) (PVDF). [9][10][11][12][13][14][15] Electrets have been used in many fields such as power generation, electrostatic cloaks, and energy harvesting. [16][17][18][19] Concerning their application in air filters, Ma et al checked the performance of portable air cleaners with various electrets.…”

Section: Introductionmentioning

confidence: 99%

Improved Electret Properties of Poly(Vinylidene Fluoride)/Lithium Niobate Nanocomposites for Applications in Air Filters

Yuan

Zhao

Dong

et al. 2019

Macro Materials & Eng

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In this work, the electret properties of poly(vinylidene fluoride) (PVDF)/lithium niobate (LiNbO3, LN) nanocomposites are systematically studied. The LN nanoparticles are fabricated by hydrothermal synthesis followed by melt‐reaction. Their morphology and crystalline structures are characterized by scanning electron microscopy (SEM) and X‐ray diffraction (XRD). The PVDF/LN nanocomposite films are prepared by solution casting with N,N‐dimethylformamide (DMF) as the solvent or melt molding. The crystalline phases of PVDF in both pure samples and nanocomposites are checked by XRD and Fourier transform infrared spectroscopy (FTIR). The measurements of the dielectric and electret properties show that the LN nanoparticles significantly increase the dielectric permittivity (ε) and the thermally stimulated discharge current (TSDC) of the samples. Such materials have potential applications including for air filters and power generators. A demonstration shows that after the same charging process, the PVDF/LN nanocomposites can absorb larger amount of polystyrene (PS) foam microparticles or micrometer size test dusts than the pure PVDF.

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Facile Fabrication of a Flexible LiNbO₃ Piezoelectric Sensor through Hot Pressing for Biomechanical Monitoring

Cited by 39 publications

References 56 publications

Human Pulse Diagnosis for Medical Assessments Using a Wearable Piezoelectret Sensing System

Human Pulse Diagnosis for Medical Assessments Using a Wearable Piezoelectret Sensing System

High‐performance poly(vinylidene fluoride)‐polyamide 11/lithium niobate nanocomposites for the applications in air filtration

Improved Electret Properties of Poly(Vinylidene Fluoride)/Lithium Niobate Nanocomposites for Applications in Air Filters

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Facile Fabrication of a Flexible LiNbO3 Piezoelectric Sensor through Hot Pressing for Biomechanical Monitoring

Cited by 39 publications

References 56 publications

Human Pulse Diagnosis for Medical Assessments Using a Wearable Piezoelectret Sensing System

Human Pulse Diagnosis for Medical Assessments Using a Wearable Piezoelectret Sensing System

High‐performance poly(vinylidene fluoride)‐polyamide 11/lithium niobate nanocomposites for the applications in air filtration

Improved Electret Properties of Poly(Vinylidene Fluoride)/Lithium Niobate Nanocomposites for Applications in Air Filters

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Facile Fabrication of a Flexible LiNbO₃ Piezoelectric Sensor through Hot Pressing for Biomechanical Monitoring