Electrostatic Induction Effects Research Articles

Implementation of multi-sensors for the measurement of pneumatically conveyed particles

Due to the complex flow state of pneumatically conveyed particles and the influence of the conveying conditions, existing measurement techniques have limitations in detecting the dynamic parameters of full-sections particles in large-scale pipelines. In order to further study and realize the measurement of local parameters of particles in pneumatic conveying pipelines, as well as to provide basic data for full-sections measurement, optimize material distribution and reduce energy consumption. Combined with electrostatic induction and piezoelectric effect, an invasive multi-sensors fusion measurement device was designed to measure local parameters such as particle velocity and mass flow rate in different areas of circular pipelines.

Advances in Multifunctional Sensors Based on Triboelectric Nanogenerator – Applications, Triboelectric Materials, and Manufacturing Integration

AbstractWith the rapid development of industry and information technology, rough challenges have been put forward for the traditional sensor technology to meet the increasingly complex and diverse application demands in actual production and daily life, and the widely distributed sensor network also faces complex power supply and maintenance problems. As a new energy conversion technology, triboelectric nanogenerators (TENGs) based on triboelectrification and electrostatic induction effect can respond to the weak mechanical stimuli in the surrounding environment and generate corresponding electrical signals to realize the sensing function without external power supply. In addition, TENGs have the advantages of wide selection of fabrication materials, flexible and diverse fundamental modes, which can be customized for different applications and realize different sensing functions. In recent years, triboelectric sensors based on TENGs have developed rapidly, and researchers have developed variable triboelectric sensors for different application scenarios. In this paper, the developed triboelectric sensos have been classified into different categories, the advanced strategy to prepare advanced triboelectric materials and technology used for manufacturing integration have been introduced. This work summarizes the main applications of triboelectric sensors and put forward the current challenges, so as to provide guidance and instructions for the future development of triboelectric sensors.

Capacitive-Coupling-Responsive Hydrogel Scaffolds Offering Wireless In Situ Electrical Stimulation Promotes Nerve Regeneration.

Electrical stimulation (ES) has shown beneficial effects in repairing injured tissues. However, current ES techniques that use tissue-traversing leads and bulky external power suppliers have significant limitations in translational medicine. Hence, exploring noninvasive in vivo ES to provide controllable electrical cues in tissue engineering is an imminent necessity. Herein, a conductive hydrogel with in situ electrical generation capability as a biodegradable regeneration scaffold and wireless ES platform for spinal cord injury (SCI) repair is demonstrated. When a soft insulated metal plate is placed on top of the injury site as a wireless power transmitter, the conductive hydrogel implanted at the injury site can serve as a wireless power receiver, and the capacitive coupling between the receiver and transmitter can generate an alternating current in the hydrogel scaffold owing to electrostatic induction effect. In a complete transection model of SCI rats, the implanted conductive hydrogels with capacitive-coupling in situ ES enhance functional recovery and neural tissue repair by promoting remyelination, accelerating axon regeneration, and facilitating endogenous neural stem cell differentiation. This facile wireless-powered electroactive-hydrogel strategy thus offers on-demand in vivo ES with an adjustable timeline, duration, and strength and holds great promise in translational medicine.

A self-powered intracardiac pacemaker in swine model

Harvesting biomechanical energy from cardiac motion is an attractive power source for implantable bioelectronic devices. Here, we report a battery-free, transcatheter, self-powered intracardiac pacemaker based on the coupled effect of triboelectrification and electrostatic induction for the treatment of arrhythmia in large animal models. We show that the capsule-shaped device (1.75 g, 1.52 cc) can be integrated with a delivery catheter for implanting in the right ventricle of a swine through the intravenous route, which effectively converts cardiac motion energy to electricity and maintains endocardial pacing function during the three-week follow-up period. We measure in vivo open circuit voltage and short circuit current of the self-powered intracardiac pacemaker of about 6.0 V and 0.2 μA, respectively. This approach exhibits up-to-date progress in self-powered medical devices and it may overcome the inherent energy shortcomings of implantable pacemakers and other bioelectronic devices for therapy and sensing.

Graphene Nanoplatelet Integrated Thermally Drawn PVDF Triboelectric Nanocomposite Fibers for Extreme Environmental Conditions

AbstractTriboelectric nanogenerators (TENGs) utilize the synergetic effect of triboelectrification and electrostatic induction to guide electrons through an external circuit, enabling low‐frequency mechanical and biomechanical energy harvesting and self‐powered sensing. Integrating 2D material with a high specific surface area into flexible ferroelectric polymers such as polyvinylidene difluoride (PVDF) has proven to be an efficient strategy to improve the performance of TENG devices. Scalable fabrication of graphene‐integrated PVDF nanocomposite fiber using thermal drawing process is demonstrated for the first time in this study. The open‐circuit voltage and short‐circuit current show 1.41 times and 1.48 times improvement with the integration of 5% graphene in the PVDF fibers, respectively. The TENG fabric shows a maximum power output of 32.14 µW at a matching load of 7 MΩ and a power density of 53.57 mW m−2. The fibers exhibit excellent stability in harsh environmental conditions such as alkaline medium, high/low temperature, multi‐washing cycle, and long‐time usage.

A Flexible and Stretchable Temperature Sensor Based on Contact Electrification for Robotic Sensing

With the rapid development of robotic systems, an increasing number of various sensitive sensors are needed to meet the requirement of data collection for unmanned detection and monitoring technology. Among various external stimuli information, temperature sensing is an essential important function that can avoid high-temperature scalding injuries, achieve robot detection of environmental, and human-machine interfaces applications. However, most of the existing temperature sensors for robotic sensing are realized by rigid materials, which have the disadvantage of not being able to adapt to an arbitrarily curved surface. Also, most of the sensors are thermistor-based approaches, which faces challenges in developing a low-cost robotic system since external power is required to obtain the sensing signal. In this work, a self-powered and stretchable temperature sensor based on Triboelectric Nanogenerator (TENG) technology was developed. The principle of TENG is the coupling effect of triboelectric charge transfer and electrostatic induction effects, which can generate different magnitudes of electrical signals when subjected to external stimuli, including temperature. To this end, this study is a pilot effort toward validating the sensitivity of TENG electrical output on different temperature effects. The surface potential of materials is explored under different temperatures by Kelvin probe force microscopy (KPFM), which shows the feasibility of self-powered temperature sensor. The proposed temperature sensor is composed of highly resilient materials physiological saline as liquid electrode encapsulated with Ecoflex as triboelectric layer, which has the advantage of biocompatibility. The temperature sensing performance was successfully maintained at 200% stretch. Owing to its flexible, bendable and stretchable characteristics, the self-powered temperature-sensitive sensor has been successfully demonstrated on a robot hand, which can read the information and respond to different temperatures through the feedback system. Overall, this self-powered temperature-sensitive sensor has great potential to be an emerging tool for human-robot interaction and automatic detection.

Conversion of Dielectric Surface Effect into Volume Effect for High Output Energy.

Improving the output energy and durability of triboelectric nanogenerators (TENGs) remains a considerable challenge for their practical applications. Owing to the interface effect of triboelectrification and electrostatic induction, thinner films with higher dielectric constants yield a higher output; however, they are not durable for practical applications. Herein, the dielectric surface effect is changed into a volume effect by adopting a millimeter-thick dielectric film with an inner porous network structure so that charges can hop in the surface state of the network. Charge migration inside the dielectric film is the key factor affecting the output of the triboelectric nanogenerator (TENG)with a thick film, based on which each working stage follows the energy-maximization principle in the voltage-charge plot. The maximum peak and average power densities of the TENG with polyurethane foam film in 1mm thickness reach 40.9 and 20.7Wm-2 Hz-1 , respectively, under environmental conditions, and the output charge density is 5.14times that of TENGs with a poly(tetrafluoroethylene) film of the same thickness. Superdurability is achieved in the rotary-mode TENGafter 200000 operation cycles. This study identifies the physical mechanism of the thick dielectric film used in TENGs and provides a new approach to promote the output and durability of TENGs.

Comparative study and multi-parameter analysis to optimize device structure of triboelectric nanogenerators

Triboelectric nanogenerator is becoming one of the most efficient energy harvesting device among all mechanical energy harvesters. This device consists of dielectric friction layers and metal electrode which generates electrical charges using electrostatic induction effect. There are several factors influencing the performance of this generator which needs to be evaluated prior to experiment. The absence of a universal technique for TENG simulation makes the device design and optimization hard before practical fabrication, which also lengthens the exploration and advancement cycle and hinders the arrival of practical applications. In order to deepen the understanding the core physic behind the working process of this device, this work will provide comparative analysis on different modes of TENG. Systematic investigation on different material combination, effect of material thickness, dielectric constant and impact of surface patterning is evaluated to shortlist the best material combination. COMSOL Multiphysics simulating environment is used to design, model and analyze factor affecting the overall output performance of TENG. The stationary study in this simulator is performed using 2D geometry structure with higher mesh density. During this study short circuit and open circuit condition were applied to observe the behavior of charge and electric potential produced. This observation is analyzed by plotting charge transfer/electric potential against various displacement distances of dielectric friction layers. The ouput is then provided to load ciruitary to measure the maximum output power of the models. Overall, this study provides an excellent understanding and multi-parameter analysis on basic theoretical and simulation modeling of TENG device.

Simulation model of a non‐contact triboelectric nanogenerator based on electrostatic induction

AbstractBased on the coupling effects of contact electrification and electrostatic induction, a triboelectric nanogenerator (TENG) can convert mechanical energy into electric power, which is at the cutting edge of alternative energy technology. Although a considerable number of TENGs with different configurations have been designed, some of them however, which only depend on the electrostatic induction effect have not received enough attention. Here, a non‐contact TENG model consists of copper rings and charged dielectric sphere is presented, which is aimed at exploring the working process of TENGs caused by electrostatic induction. Two classical models, including vertical and horizontal double copper rings models are also proposed. Relevant advanced and accurate models of TENGs have been established through the finite element method. We anticipate that the constructed model and theoretical analysis are helpful for the design of non‐contact model TENGs with complicated geometric construction, and expand their applications in various fields.image

Foam nickel-PDMS composite film based triboelectric nanogenerator for speed and acceleration sensing

As a new energy conversion technology, triboelectric nanogenerator (TENG) can use the coupling of triboelectrification and electrostatic induction effect to convert tiny mechanical energy into electrical energy, powering small electronic devices. In this paper, a vibration sensing triboelectric nanogenerator (V-TENG) based on a foam nickel-PDMS composite film was prepared, which can convert low frequency and small-amplitude mechanical energy into electrical energy, and the open circuit voltage of V-TENG can reach 3.6V at a vibration frequency of 4 Hz. In addition, the V-TENG can be used as a self-powered speed/acceleration sensor to detect speed changes in the range of 0.3 m/s to 1.5 m/s and acceleration changes in the range of 3 m/s2 to 13 m/s2.

Eye tracking and eye expression decoding based on transparent, flexible and ultra-persistent electrostatic interface

Eye tracking provides valuable insight for analyzing visual attention and underlying thinking progress through the observation of eye movements. Here, a transparent, flexible and ultra-persistent electrostatic sensing interface is proposed for realizing active eye tracking (AET) system based on the electrostatic induction effect. Through a triple-layer structure combined with a dielectric bilayer and a rough-surface Ag nanowire (Ag NW) electrode layer, the inherent capacitance and interfacial trapping density of the electrostatic interface has been strongly enhanced, contributing to an unprecedented charge storage capability. The electrostatic charge density of the interface reached 1671.10 μC·m−2 with a charge-keeping rate of 96.91% after 1000 non-contact operation cycles, which can finally realize oculogyric detection with an angular resolution of 5°. Thus, the AET system enables real-time decoding eye movements for customer preference recording and eye-controlled human-computer interaction, supporting its limitless potentiality in commercial purpose, virtual reality, human computer interactions and medical monitoring.

Advances in Triboelectric Flow Sensor

AbstractWith the rapid development of advanced materials and manufacturing technologies, flow sensors have made significant progress in the field of mechanical engineering, which could cater to the development trend of the Internet of Things (IoT) and the ongoing Fourth Industrial Revolution. However, traditional power supply modes such as lithium batteries require regular recharging or replacement, which greatly causes too much inconvenience and maintenance consumption, and may also pose potential risks to the marine environment. The triboelectric nanogenerators (TENGs), based on the coupling effect of contact electrification and electrostatic induction, have been demonstrated to convert mechanical movements of the fluid into electrical signals with various features such as flexibility, conformability, and user‐friendliness. This review systematically summarizes for the first time the fundamental working mechanism, rational structural design, and analysis of practical application scenarios of triboelectric flow sensor as an emerging technology for flow monitoring of the Industrial IoT. According to the different fluid objects monitored, the latest representative achievements of triboelectric flow sensors can be divided into gas flow sensors, liquid flow sensors, and two‐phase flow sensors. Finally, the current challenges and future development directions of triboelectric flow sensors are examined, which can promote the further development of the field of the flow sensors.

Relationship between output voltage of water droplet-based electricity nanogenerator and electrolyte concentration

Droplet-based electricity generators (DEGs) that convert mechanical energy from falling droplets into electricity based on the coupling effect of triboelectrification and electrostatic induction are candidates for sustainable energy harvesters because of their low production costs and simple fabrication. The DEG is composed of an electrode and friction layer which is easily charged and generates electricity when the droplet flows on the surface of friction layer. Although environmental water is used to harvest energy, it contains impurities, organic substances, and electrolytes that may influence the electrical output of the DEG. Herein, the DEG output voltage and current were measured for different electrolyte species and concentrations, and a relationship between them was established. The output voltage was enhanced by increasing the electrolyte concentration until a certain concentration was reached, thereafter, at higher concentrations, the output decreased exponentially. This behavior implies that the charge on friction layer is neutralized by cations in the residue solution, and the output is decreased. Using rainwater, river water, and seawater collected from the environment, the DEG outputs were compared. Rainwater was found to be the most suitable water resource for energy harvesting because it had the highest voltage of the three types of water. This study provides guidelines for the use of DEGs in environments with various electrolyte concentrations.

Liquid metal based triboelectric nanogenerator with excellent electrothermal and safeguarding performance towards intelligent plaster

Polymer-based self-powered wearable sensing devices are easily destroyed under harsh mechanical shocks which largely restricts the development of smart electronic device. Herein, a versatile liquid metal based triboelectric nanogenerator (LM-TENG) device was developed by integrating the shear stiffening elastomer (SSE) with liquid metal (LM) and electrothermal aluminum foil. Based on the electrostatic induction effect, LM-TENG showed the good capacity of harvesting energy. The output voltage and power of the LM-TENG reached to 22.29 V and 55.16 µW with 9 MΩ load resistance at the force and frequency of 40 N and 15 Hz. Besides, LM-TENG demonstrated excellent electrothermal performance by efficiently reaching 69.02 ℃ with the applied voltage of 1.5 V. Additionally, LM-TENG displayed safeguarding performance under quasi-static and dynamic damage by effectively decreasing the impact force from 2.86 to 0.72 kN, endowing the device with excellent anti-impact from sharp objects penetration loading. Moreover, the utility of LM-TENG as intelligent medical plaster with joule-heating, controllable stiffness, self-powering sensing and anti-impact performance was further studied, providing a new strategy for designing multifunctional sensor, and paving the way for intelligent wearable electronics, personal healthcare and safeguards in the future.

Mylar Interlayer-Mediated Performance Enhancement of a Flexible Triboelectric Nanogenerator for Self-Powered Pressure Sensing Application

A triboelectric nanogenerator (TENG) is a green energy harvester that transforms mechanical energy from the surroundings and body movements into useful electrical energy by the combined effect of triboelectrification and electrostatic induction. Here, we have developed a flexible organic–inorganic film-based contact separation mode TENG with polyvinyl butyral (PVB) and indium oxide (IO) films as contact materials. A biaxially oriented polyethylene terephthalate (BoPET) film (known as “Mylar”) has been used as the charge transition-blocking interlayer between the PVB triboelectric layer and the electrode, which prevents the recombination of generated charges with the interfacial charges on the electrode and thereby enhances the electrical output performance. The fabricated flexible PVB-IO TENG having a contact area of 4 cm2 and a separation gap of 5 mm generates an output voltage and a short-circuit current density of ∼700 V and ∼1.52 mA/m2, respectively. An enhancement of ∼85-fold in the peak power density is obtained for the PVB-IO TENG with the BoPET layer at a load resistance of 200 MΩ in comparison with the one without the BoPET interlayer. The as-fabricated device was used for capacitor charging and powering electronic gadgets such as digital thermometers, calculators, and LEDs. Also, the developed PVB-IO TENG has been demonstrated for the mechanical energy scavenging from human motions such as finger tapping, palm tapping, finger bending, and elbow bending. Moreover, the PVB-IO TENG was structurally modified into a self-powered pressure sensor by reducing its contact area and separation gap, which exhibits an excellent sensitivity of ∼4.38 V/kPa in the pressure range from 0.5 to 16 kPa.

High-performance flexible pentacene transistor memory with PTCDI-C13 as N-type buffer layer

Flexible organic field-effect transistor nonvolatile memories (OFET-NVMs) with polymer electrets have aroused great attention for its important role in next-generation flexible data storage devices application. However, the OFET-NVMs to date still hardly reach the requirements for practical applications. In air environment, the positively charged defects formed in pentacene near the interface with polymer, result in unsatisfied high programming/erasing (P/E) voltages. Here, we propose an OFET memory structure, in which an n-type semiconductor N, N′-Bis(3-pentyl) perylene-3, 4, 9, 10-bis(dicarboximide) (PTCDI-C13) is inserted between pentacene and poly(4-vinyl phenol. Based on the electrostatic induction effect, electrons are induced on the surface of PTCDI-C13 due to the electrostatic field generated by the positive charges at the interface of pentacene/polymer, and compensate part of the positive charges at the interface, resulting in the reduction of the height of hole-barrier. The flexible memory device with PTCDI-C13 exhibits a memory window of larger than 7 V at P/E voltages (±20 V), fast switching speeds (0.5 ms), good P/E endurance (>400 cycles), large field-effect mobility (0.026 cm2 V−1 s−1), and long retention time (over 104 s).

A novel hybrid triboelectric nanogenerator based on the mutual boosting effect of electrostatic induction and electrostatic breakdown

A novel hybrid triboelectric nanogenerator integrating AC- and DF-triboelectric nanogenerators is developed, with a switchable dual-output feature, and the mutual boosting effect of electrostatic induction and electrostatic breakdown is identified.

A Stretchable Expanded Polytetrafluorethylene-Silicone Elastomer Composite Electret for Wearable Sensor.

Soaring developments in wearable electronics raise an urgent need for stretchable electrets. However, achieving soft electrets simultaneously possessing excellent stretchability, longevity, and high charge density is still challenging. Herein, a facile approach is proposed to prepare an all-polymer hybrid composite electret based on the coupling of elastomer and ePTFE membrane. The composite electrets are fabricated via a facile casting and thermal curing process. The obtained soft composite electrets exhibit constantly high surface potential (-0.38 kV) over a long time (30 days), large strain (450%), low hysteresis, and excellent durability (15,000 cycles). To demonstrate the applications, the stretchable electret is utilized to assemble a self-powered flexible sensor based on the electrostatic induction effect for the monitoring of human activities. Additionally, output signals in the pressure mode almost two orders of magnitude larger than those in the strain mode are observed and the sensing mechanism in each mode is investigated.

Trampoline-Shaped Micro Electric-Field Sensor for AC/DC High Electric Field Measurement

The measurement of high electric field is widely used in applications such as power grid, electrical equipment, space launch, petroleum industry, and meteorological monitoring. Traditional electric field measurement methods, such as field mills, are bulky and cause electric field distortion. In this article, we presented a trampoline-shaped microelectric field sensor (E-sensor) based on microelectromechanical system (MEMS). The micro E-sensor uses the effect of electrostatic induction, which generates force that drives the vibration of a piezoresistive film and converts the electric field into a differential voltage signal. The presented E-sensor can measure both ac and dc high electric fields with relatively high resolution and wide range. Through experimental measurement, the device exhibits an ac resolution of 172 V/m/Hz <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1/2</sup> and a linear measurable electric field range of 312 V/m to over 700 kV/m. The presented E-sensor has good performance with mm-level size and low cost, which could be mass produced for broad applications.

Analysis of monitoring effect on Hybrid Electric Field for AC/DC Cross Line

Electrostatic induction charge which generated by the coupling effect of hybrid electric field of AC/DC cross line and metal object under the transmission line can cause different levels of electric shock injury to human. In order to find out the distribution law of the hybrid electric field and reduce the effect of electrostatic induction, this paper set up shielding lines which paralleled to the AC and DC lines respectively on the outside of the side conductors and along the diagonal of parallelogram at crossing point, then measured the electric field distribution in shielding areas of 750kV AC and 500kV DC lines and the induced voltages of shielding lines in different states, analyzed the effect of shielding line on power frequency electric field and DC composite electric field. The results showed that shielding lines have a reducing effect on the hybrid electric field of the cross lines, the average power frequency field strength is reduced by 12.6%, the DC composite field and power frequency electric field at the crossing position was far less than the limits specified in the respective standards. Both induced voltage of bare lines and shielding lines wrapped with adhesive tape increase with the raise of erection height. Under the same conditions, the average induction voltage of bare conductor is 9.3% higher than that of shielding lines wrapped with adhesive tape. There is no obvious difference between parallel and vertical erection methods of the same number of shielding lines in the degree of reduction of induced voltage.