Discovery Of Piezoelectricity Research Articles

Electromechanical Coupling in Collagen Measured under Increasing Relative Humidity.

The functional role of collagen piezoelectricity has been under debate since the discovery of piezoelectricity in bone in 1957. The possibility that piezoelectricity plays a role in bone remodeling has generated interest in the investigation of this effect in relevant physiological conditions; however, there are conflicting reports as to whether collagen is piezoelectric in a humid environment. In macroscale measurements, the piezoelectricity in hydrated tendon has been shown to be insignificant compared to dehydrated tendon, whereas, at the nanoscale, the piezoelectric effect has been observed in both dry and wet bone using piezoresponse force microscopy (PFM). In this work, the electromechanical properties of type I collagen from a rat tail tendon have been investigated at the nanoscale as a function of humidity using lateral PFM (LPFM) for the first time. The relative humidity (RH) was varied from 10% to 70%, allowing the piezoelectric behavior to be studied dry, humid, as well as in the hydrated range for collagen in physiological bone (12% moisture content, corresponding to 40-50% RH). The results show that collagen piezoresponse can be measured across the humidity range studied, suggesting that piezoelectricity remains a property of collagen at a biologically relevant humidity.

Peptide Coassembly to Enhance Piezoelectricity for Energy Harvesting.

The discovery of piezoelectricity in self-assembled peptide nanostructures opens an avenue to a new regime of piezoelectric materials and enables the fundamental investigation of electromechanical coupling in biomaterials. However, strategies for fabricating peptides with desired properties are still lacking. We find that a peptide-based coassembly process effectively controls the properties of peptide nanomaterials and demonstrates their application potential in nanogenerators. The composing peptides and their concentration influence the morphology, molecular property, and physical property of coassembled crystals. Compared with self-assembled diphenylalanine peptides, the coassembled peptides of diphenylalanine and phenylalanine-tryptophan show a 38% increase in piezoelectric coefficient, and the resulting harvesting device shows nearly a 3-fold increase in open-circuit voltage outputs.

Solution processable poly(vinylidene fluoride)-based ferroelectric polymers for flexible electronics

Since the discovery of piezoelectricity in poly(vinylidene fluoride) (PVDF) 50 years ago, ferroelectric polymers have established their own areas for research and applications due to their unique properties in comparison to single crystals and inorganics. PVDF is a semicrystalline polymer that can crystallize into five different polymorphs. Among them, the polar β-phase is the most interesting one for electroactive properties because it has the highest dipolar moment and the highest piezoelectric response. In the early days, the β-PVDF was typically produced by melt processing, limiting its form to free-standing films. The rapid development of flexible electronics, however, highly requires β-PVDF fabricated from solutions under mild conditions. The objective of this perspective is to summarize the effective methods to produce β-PVDF from solution, to present the approaches for enhancing the electroactive properties through morphological controls, and to discuss the applications of PVDF-based ferroelectric polymers in flexible electronics. In addition, current challenges that may impede the further development of this field are pointed out.

Self-Powered 2D Material-Based pH Sensor and Photodetector Driven by Monolayer MoSe2 Piezoelectric Nanogenerator.

The large piezoelectricity of monolayer MoSe2, which is predicted to be stronger than that of all of the other group VIB transition-metal dichalcogenides (including MoS2), has only been theoretically investigated. Here, we report experimental evidence of in-plane piezoelectricity in MoSe2. Monolayer single-crystalline MoSe2 flake derived from chemical vapor deposition demonstrates a peak output voltage of 60 mV at 0.6% strain, which is ∼50% larger than that of MoS2. Piezoelectric signal along the armchair orientation of MoSe2 is ∼6 times larger than that along the zigzag orientation, indicative of strong anisotropic piezoelectricity. Piezoelectric nanogenerator based on a single MoSe2 flake illustrates remarkable electromechanical conversion ability, and thus is able to noninvasively monitor vital health signs, such as respiratory rate and heart rate. Despite the extremely small size, MoSe2 nanogenerator is able to drive pH sensor based on MoS2 and photodetector based on MoS2/WSe2 heterojunction due to the outstanding piezoelectricity of MoSe2 and the ultralow power consumption of two-dimensional (2D) material sensors. The self-powered, solely 2D-material-based sensor units demonstrate superb sensing performance. Therefore, the discovery of piezoelectricity in monolayer MoSe2 provides a route for achieving self-powered atomic-scale electromechanical systems that could stimulate further fundamental research and potential applications.

Graphene Oxide Reinforcement Enhances the Piezoelectric and Mechanical Properties of Poly(3-hydroxybutyrate-co-3-hydroxy valerate)-Based Nanofibrous Scaffolds for Improved Proliferation of Chondrocytes and ECM Production.

The discovery of piezoelectricity in natural cartilage has inspired the development of piezoelectric biomaterials for its repair and regeneration using tissue engineering approaches. In the present work, piezoelectric scaffolds composed of poly(3-hydroxybutyrate-co-3-hydroxy valerate) (PB) and graphene oxide (GO) have been successfully fabricated by the electrospinning technology. The fabricated scaffolds were examined for their morphological, physical, chemical, piezoelectric, and biological characterizations. The fiber diameter was found to be in the range of 600-800 nm appropriate for chondrogenic growth. Reinforcement of 1.5% GO enhanced the tensile strength of PB to 2.08 ± 0.33 MPa compared to PB alone (0.59 ± 0.12). Reinforcement of GO significantly enhances the piezoelectric coefficient (d33), and for 0.5, 1, and 1.5% GO in PB, it was found to be 0.12 ± 0.015, 0.57 ± 0.19, and 0.94 ± 0.03 pC/N, respectively, and corresponding voltages of 11.84 ± 1.4, 54.69 ± 18.29, and 100.2 ± 3.2 mV, respectively, were generated. The biological activity of the smart piezo scaffolds was also evaluated on freshly isolated goat chondrocytes. The GO-reinforced scaffold showed higher cell proliferation and cell adhesion as confirmed by alamarBlue assay and field emission scanning electron microscopy imaging. The GO-reinforced scaffold has demonstrated significantly higher extracellular matrix production compared to PB as confirmed by histochemistry and real-time polymerase chain reaction. Hence, the GO-based piezoelectric PB electrospun scaffold can be a better alternative for cell-free and growth factor-free approach for cartilage tissue engineering.

Piezoelectricity in Multilayer Black Phosphorus for Piezotronics and Nanogenerators.

Recently, piezoelectric characteristics have been a research focus for 2D materials because of their broad potential applications. Black phosphorus (BP) is a monoelemental 2D material predicted to be piezoelectric because of its highly directional properties and non-centrosymmetric lattice structure. However, piezoelectricity is hardly reported in monoelemental materials owing to their lack of ionic polarization, but piezoelectric generation is consistent with the non-centrosymmetric structure of BP. Theoretical calculations of phosphorene have explained the origin of piezoelectric polarization among P atoms. However, the disappearance of piezoelectricity in multilayer 2D material generally arises from the opposite orientations of adjacent atomic layers, whereas this effect is limited in BP lattices due to their spring-shaped space structure. Here, the existence of in-plane piezoelectricity is experimentally reported for multilayer BP along the armchair direction. Current-voltage measurements demonstrate a piezotronic effect in this orientation, and cyclic compression and release of BP flakes show an intrinsic current output as large as 4 pA under a compressive strain of -0.72%. The discovery of piezoelectricity in multilayer BP can lead to further understanding of this mechanism in monoelemental materials.

Fabrication of Biocompatible Potassium Sodium Niobate Piezoelectric Ceramic as an Electroactive Implant.

The discovery of piezoelectricity in natural bone has attracted extensive research in emulating biological electricity for various tissue regeneration. Here, we carried out experiments to build biocompatible potassium sodium niobate (KNN) ceramics. Then, influence substrate surface charges on bovine serum albumin (BSA) protein adsorption and cell proliferation on KNN ceramics surfaces was investigated. KNN ceramics with piezoelectric constant of ~93 pC/N and relative density of ~93% were fabricated. The adsorption of protein on the positive surfaces (Ps) and negative surfaces (Ns) of KNN ceramics with piezoelectric constant of ~93 pC/N showed greater protein adsorption capacity than that on non-polarized surfaces (NPs). Biocompatibility of KNN ceramics was verified through cell culturing and live/dead cell staining of MC3T3. The cells experiment showed enhanced cell growth on the positive surfaces (Ps) and negative surfaces (Ns) compared to non-polarized surfaces (NPs). These results revealed that KNN ceramics had great potential to be used to understand the effect of surface potential on cells processes and would benefit future research in designing piezoelectric materials for tissue regeneration.

Piezoelectricity in screen-printed hydroxyapatite thick films

ABSTRACTThe discovery of piezoelectricity in calcined thin films and sintered ceramics of synthetic hydroxyapatite is of interest to understand the role of electricity in bone growth and to find use of piezoelectric implants in bone growth stimulation or deceleration and in energy harvesting to run spinal or neuro stimulators. Synthetic apatites including hydroxyapatite and a mixture of hydroxyapatite and tricalcium phosphates are extensively used in bone graft substitute and cement-less implant coating. We provide experimental evidence of piezoelectricity in screen-printed thick-films of hydroxyapatite, which may allow many real-time experiments to understand physiological significance of piezoelectricity and potential in vivo exploitation.

Piezoelectric nanogenerators – a review of nanostructured piezoelectric energy harvesters

A huge number of piezoelectric materials have been demonstrated since the discovery of piezoelectricity over a century ago. The use of nanostructured piezoelectrics, however, is a relatively recent development, and the understanding of the nanoscale size effects on ferro- and piezoelectricity is still being formulated. Despite this, the application of piezoelectric nanostructures to energy harvesting has expanded rapidly in the last decade leading to a huge range of reported devices [96,97]. Most studies focus on zinc oxide, as its nanostructures are formed relatively easily using low temperature methods [98], unlike many ferroelectrics which require high temperature processing. In addition, the nanostructures are crystallographically aligned and non-ferroelectric, and therefore do not require poling. However, more recently other well-known materials have been investigated for nanostructured energy harvesters including lead zirconate titanate (PZT) and barium titanate, with the potential for higher power outputs due to their higher piezoelectric coefficients. This review summarises the work to date on nanostructured piezoelectric energy harvesters, commonly called nanogenerators, starting with early reports of piezoelectric output from single strained ZnO nanorods, and moving through the use of nanorod arrays, flexible substrates and alternative materials and nanostructures. Applications that have been demonstrated for devices are summarised, and the future prospects for this field are considered. Before embarking on the development of any nanostructured energy harvesters a thorough understanding of piezoelectric and ferroelectric materials – and the broader energy harvesting field – is essential, for which there are a number of suitable reviews and textbooks [1–4].

PZT to Lead Free Piezo Ceramics: A Review

The growth of piezo science is phenomenal since the discovery of piezoelectricity in 1880. Among various piezoelectric materials, lead zirconate titanate (PZT) is a very popular and exhaustively studied piezo system which allows synthesis of large number of materials with wide range of properties due to formation of solid solutions over large range of Zr:Ti ratio. Also, this system accommodates wide range of dopants for modification of crystal structure. Due to this versatile nature, PZT has emerged as very popular among users and researchers worldwide. However, considering the toxicity of lead oxide, development of lead free piezo ceramics is encouraged in recent years. Some lead free piezo material systems such as BNT, BKT, KNN, BZT-BCT have been explored. However, development of lead free piezo devices and their performance in comparison with PZT devices are yet to be established. At this juncture, it was felt that an article reviewing the current status of development of piezo materials highlighting the change from PZT to various lead free systems would be of very much interest to the researchers. Therefore, efforts are made to bring out the recent developments on R&D of piezo materials in this review article.

Why is a new journal dedicated to echocardiography required?

Why is a new journal dedicated to echocardiography required?

Process Crystallographic Simulation for Biocompatible Piezoelectric Material Design and Generation

From 1880’s discovery of piezoelectricity by French physicists Jacques and Pierre Curie, a huge number of piezoelectric materials have been developed and applied to the industrial equipment and scientific instrument. In the middle of 20th century, most widely used ceramic piezoelectric materials, BaTiO3 (BTO) in 1944, PbTiO3 in 1950, and Pb(Zr,Ti)O3 (PZT) in 1955, were discovered through “hermetic art approach.” It was not CAE driven material discovery. Actually, the experimental trial and error approach is inefficient way for the material discovery. Therefore a new CAE technique to develop a new high performance piezoelectric material under a short lead time is strongly required. It can analyze material characteristics, and design material structure and generation process simultaneously before actual production. This overall CAE technique for new material design and generation, which can be called as “process crystallographic simulation,” is discussed in this state-of-the-art paper, which will be able to establish a new concept of material and process design.

The evolution of time measurement, Part 2: quartz clocks [Recalibration

Quartz clocks are the most common timekeepers of all. Billions of quartz oscillators are manufactured annually for use inside clocks, watches, mobile phones, computers, radios, and televisions. In this article, Part 2 of a five-part series, I discuss the evolution of quartz clocks, beginning with the discovery of piezoelectricity.

Imagerie de l’encéphale, de la cellule à l’organe

Brain imaging has progressed over the centuries, from prehistory (surgical and sculptural empiricism), through the Middle Ages (dissection and drawings), the Renaissance (printing) and the 18th century (Spallanzani and ultrasounds), to the 19th century and the discovery of piezoelectricity by the Curie brothers and X-rays by Röntgen in 1895. The head had finally become transparent! The microscope was used by Ramon Y Cajal for histological and neuropathological brain studies. Marie Curie's discovery of radioisotopes paved the way for advances in in vivo neurophysiology. In the 20th century, technical progress accelerated with the advent of computed tomography. Injected contrast products were initially negative (air for ventriculography and pneumo-encephalography), and subsequently positive (intraventricular then intraarterial iodine, cerebral arteriography, increasingly hyperselective). Neurology and neurosurgery were followed by neuroradiology, stereotaxy, and interventional neuroradiology. G.N. Hounsfield's EMI CT scanner replaced silver salts crystals with computed pixels and voxels. Magnetic resonance imaging (MRI, 1981), which dispenses with the need for X-rays, is evolving at the same pace as computer science itself (Moore's Law) in the form of nanometric biophotonics for example. Diffusion MRI is providing precious information on neuroanatomy (axonal organization of the white matter and neuro-tractography, vascular anatomy), neurochemistry (MRS) and neurophysiology. Functional MRI of sensory activation and resting connectivity, the substrate of thought, is giving fascinating results. Functional stereotactic neurosurgery (for epilepsy, abnormal movements, etc.), stereotactic radiosurgery and endovascular interventional neuroradiology are among the latest approaches.

The History of Sonographers

I thank all who have made it possible for me to write this history by giving me an opportunity to be a part of it. I also thank Ann Polin, Carolyn Coffin, and Jean Lea Spitz for assistance. Abbreviations ACR, American College of Radiology; AIUM, American Institute of Ultrasound in Medicine; AMA, American Medical Association; ARDMS, American Registry of Diagnostic Medical Sonographers; ASE, American Society of Echocardiography; ASUTS, American Society of Ultrasound Technical Specialists; CAHEA, Committee on Allied Health Education and Accreditation; JRCDMS, Joint Review Committee on Education in Diagnostic Medical Sonography; SDMS, Society of Diagnostic Medical Sonographers/Society of Diagnostic Medical Sonography; SVT, Society of Vascular Technology; WFUMB, World Federation for Ultrasound in Medicine and Biology ne of the most important questions to be answered when writing a history of the profession is where to begin. Pythagoras certainly played a role when he observed the relationship between sound pitch and frequency, but he did not make this observation related to medicine. John William Strutt, the third Baron Rayleigh, one of the few members of nobility to also be an outstanding scientist and 1904 Nobel Prize winner, published among many works the Theory of Sound. Christian Doppler lent his name to the Doppler effect, something we use every day when performing sonographic procedures. But many think that the true conception of ultrasound occurred in 1880 with the discovery of piezoelectricity by the French physicist Pierre Curie. Along with his brother Jacques, he performed experiments that showed that when certain crystals are subjected to an electrical field, they can be made to expand and contract, converting electrical into mechanical energy. These piezoelectric crystals can then act as both transmitters and receivers of sound. Since the early days of medicine, there has been a great desire to “see” inside the body. This is what drove Roentgen to develop x rays in 1895, Helmholtz the ophthalmoscope in 1851, Garcia the laryngoscope in 1854, and Nitze the cystoscope in 1876. Sound was first applied to the human body through auscultation in 1761 and the stethoscope in 1819, and interpreting these sounds required imagination, as did interpreting the early sonographic images. In the beginning, Doppler ultrasound was also strictly an analysis of audible sound.1,2 The use of ultrasound in medicine is similar to many technologic advances that owe their fame to war. The French government asked Paul Langevin, PhD, to develop a device capable of detecting submerged enemy submarines. The device he developed used the piezoelectric effect, which he had learned as a student with the Curies. He used quartz crystals and vacuum tube amplifiers, which were also used with early medical ultrasonic transducers. This was considered the first ultrasonic device. This research was not completed in time to be applied to the war effort. However, it did form the basis of sound navigation ranging (SONAR) detection, which was further developed during the Second World War.1,2

Kelvin and piezoelectricity

This paper presents a résumé of the history of piezoelectricity during the 19th and20th centuries. By examining the experiments, concepts and theoriespresented in Lord Kelvin’s scientific communications and those of hiscontemporaries, this paper aims to show that he played an important role inthe development of piezoelectricity. Kelvin’s contribution was that heproduced the measurement instrumentation that led to the discovery ofpiezoelectricity and laid some of the essential theoretical groundwork that ledto the important applications of piezoelectricity in the 20th century.

History and recent progress in piezoelectric polymers

Electrets of carnauba wax and resin have exhibited good stability of trapped charges for nearly 50 years. Dipolar orientation and trapped charge are two mechanisms contributing to the pyro-, piezo-, and ferroelectricity of polymers. Since the 1950s, shear piezoelectricity was investigated in polymers of biological origin (such as cellulose and collagen) as well as synthetic optically active polymers (such as polyamides and polylactic acids). Since the discovery of piezoelectricity in poled polyvinylidene fluoride (PVDF) in 1969, the pyro-, piezo-, and ferroelectricity were widely investigated in a number of polar polymers, such as copolymers of vinylidene fluoride and trifluoroethylene, copolymers of vinylcyanide and vinylacetate, and nylons. Recent studies involve submicron films of aromatic and aliphatic polyureas prepared by vapor deposition polymerization in vacuum and the piezoelectricity of polyurethane produced by the coupling of electrostriction and bias electric fields. Gramophone pickups using a piece of bone or tendon were demonstrated in 1959. Microphones using a stretched film of polymethyl glutamate were reported in 1968. Ultrasonic transducers using elongated and poled films of PVDF were demonstrated in 1972. Headphones and tweeters using PVDF were marketed in 1975. Hydrophones and various electromechanical devices utilizing PVDP and its copolymers have been developed during the past 30 years. This paper briefly reviews the history and recent progress in piezoelectric polymers.

The electrostriction of dielectrics

The deformation of bodies in an electric field was first observed by Fontana [1] and Volpicelli [2], and Outer [3] analyzed the phenomenon quantitatively. Lippman predicted the phenomenon of electrostriction from general thermodynamic principles after the discovery of piezoelectricity by the Curie brothers [4].