Accumulation Of Static Charges Research Articles

Thermodynamic driving forces in contact electrification between polymeric materials

Contact electrification, or contact charging, refers to the process of static charge accumulation after rubbing, or even simple touching, of two materials. Despite its relevance in static electricity, various natural phenomena, and numerous technologies, contact charging remains poorly understood. For insulating materials, even the species of charge carrier may be unknown, and the direction of charge-transfer lacks firm molecular-level explanation. Here, we use all-atom molecular dynamics simulations to investigate whether thermodynamics can explain contact charging between insulating polymers. Based on prior work suggesting that water-ions, such as hydronium and hydroxide ions, are potential charge carriers, we predict preferred directions of charge-transfer between polymer surfaces according to the free energy of water-ions within water droplets on such surfaces. Broad agreement between our predictions and experimental triboelectric series indicate that thermodynamically driven ion-transfer likely influences contact charging of polymers. Furthermore, simulation analyses reveal how specific interactions of water and water-ions proximate to the polymer-water interface explain observed trends. This study establishes relevance of thermodynamic driving forces in contact charging of insulators with new evidence informed by molecular-level interactions. These insights have direct implications for future mechanistic studies and applications of contact charging involving polymeric materials.

An antistatic agent based on polyionic liquid applied to nylon 6

In order to improve the electrical conductivity of nylon 6 (PA6) and avoid misfires and explosions caused by static charge accumulation, a quaternary ammonium salt polyionic liquid (PIL) antistatic agent was synthesized in this paper. The surface resistance of PA6 was reduced to 108 Ω with the addition of 2 wt% antistatic agent, and the mechanical properties and aging resistance of the substrate were improved. Meanwhile, the morphology and crystallinity of PIL/PA6 composites were further characterized by scanning electron microscope (SEM), energy dispersion spectrometer (EDS) and X-ray diffraction (XRD). It is worth noting that the quaternary ammonium salt polyionic liquid antistatic agent synthesized in this paper has the advantages of excellent antistatic effect, durability, low cost, and simple reaction condition, so it has a broad application prospect in the antistatic aspect of PA6.

Fabrication of halogen-free and phosphorus-free flame retardant and antistatic PAN fibers based on tea polyphenol phenolic resin chelated with iron (Ⅲ) ions

Polyacrylonitrile (PAN) fibers are one of the three major synthetic fibers in the world, but the drawbacks of flammable and static charge accumulation limit their application. To address the issue, tea polyphenol phenolic resin (TPPR) was firstly prepared from biomass tea polyphenol in this paper. Next, TPPR was blended with PAN spinning solution and wet-spun with Fe3+ solution as coagulation bath to construct phosphorus-free and halogen-free flame retardant PAN fibers (TPPR@Fe/PAN). The results indicated that the limiting oxygen index (LOI) value increased from (17.3 ± 0.51)% of PAN fibers to (31.6 ± 0.51)% of TPPR@Fe/PAN. Even after 30 laundering cycles (LCs), the LOI value of TPPR@Fe/PAN was still up to (27.7 ± 0.51)%, indicating good washing durability. Additionally, the heat release capacity (HRC) and total heat release (THR) of TPPR@Fe/PAN had 35.0% and 48.6% reduction, respectively. Furthermore, TPPR@Fe/PAN obtained excellent antistatic ability. Besides, the TG-IR results demonstrated that both the release of flammable and toxic gases were significantly suppressed. In the work, a simple and feasible flame retardant and antistatic strategy was established which was convenient for fabrication of functional PAN fibers on a large scale.

Performance Assessment of Frequency Selective Grounding for Grid-Connected Photovoltaic Systems

Photovoltaic (PV) panels and their grid-connection circuitries have to be grounded to comply with various standards and industrial codes. Objectives of grounding a PV system include limiting ground currents and potentials, supporting the operation of protective devices therein, and preventing the accumulation of static charges on PV panels. These objectives can be translated into design constraints for an impedance to connect a PV system to the ground. This paper presents the design and performance assessment of a frequency selective grounding (FSGR) for grid-connected PV systems. The proposed FSGR is composed of a parallel <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$R$</tex-math></inline-formula> , <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$L$</tex-math></inline-formula> , and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$C$</tex-math></inline-formula> circuit, which provides a resistive path for dc currents and a low capacitive impedance path for harmonic currents. The FSGR is designed and experimentally tested for a 2 kW, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$3\phi$</tex-math></inline-formula> , laboratory grid-connected PV system under fault and non-fault conditions. The performance of the proposed grounding is also compared with the solid grounding under similar conditions to further assess its capabilities. Experimental results show that the FSGR can reduce ground currents, limit ground potentials, and reduce the dc leakage currents. These observed features are complimented with minor effects on the operation of protective devices in a grid connected PV system.

Study of static charge accumulation in HDPE gas pipelines

The accumulation of static charge in polyethylene pipes of gas network systems is a familiar process, which is paid attention to mainly to prevent accidents on pipelines. incidents related to static electricity can occur both during assembly works (coil tapping) and during the operation of gas pipelines (gas venting, etc.). Despite the fact that repeated attempts to study this process have been made by major operating organizations, today we can state that these regularities have not been studied in full. In this work we have made an attempt to describe theoretically the process of static charge accumulation on a pipe body, as well as to evaluate experimentally the adequacy of the proposed models.

An On-Chip ESD Sensor for Use in Advanced Packaging

Electrostatic discharge (ESD) failure results in about 35% of integrated circuit (IC) field return and causes several billion-dollar losses to the semiconductor industry per year. Most modern ICs include on-chip ESD protection circuitry which comes at the cost of I/O performance. Static charge accumulation during transport and handling may exceed the limits of this ESD protection and cause damage to the ICs. Modern advanced packaging technologies are not amenable to rework if one or more components are ESD compromised. An on-chip ESD sensor is useful in identifying and preventing the assembly of ESD compromised dielets in any advanced packaging technology. Two approaches for on-chip ESD sensor that can be employed on any die, following the ground rules within that technology are presented. Both approaches are designed, simulated, fabricated, and experimentally characterized using GlobalFoundries 22-nm fully depleted silicon-on-insulator (FDSOI) technology. While determining ESD voltage using sensors, we encounter two events that are naturally random. First, ESD is a random event with some probability distribution function (PDF) with respect to voltage. In addition, oxide breakdown within the ESD sensors is also random with a Weibull distribution. A Bayesian method is developed for the estimation of ESD voltage PDF using sensors. Experimental testing of the sensors using an ESD gun and ESD voltage estimation from the number of sensors that broke down is presented. The estimated ESD voltage closely matches the ESD voltage that the dies were subjected to during experimental verification.

High sensitivity Thomson spectrometry: analysis of measurements in high power picosecond laser experiments

Thomson spectrometers (TS) are designed to detect and distinguish protons from heavier ions in experiments of intense laser-matter interaction. The combination of electric and magnetic field allows for deflecting ion species with different mass-to-charge ratio on different trajectories. However, even small distortions of the internal fields of the device can lead to a degradation of the measurement quality. Hence, TS are sensitive to both high electromagnetic pulses (EMPs) and fields due to static charge accumulation caused by the interaction. Here we report on the analysis of data obtained with a TS designed to have high sensitivity and robustness with, optimized shielding against EMPs, even when the device is placed at short distances from the interaction point, where the electromagnetic radiation is more intense. To test this, the spectrometer was thus placed ∼50 cm far from the target during an experiment at the PHELIX laser at GSI (∼180 J energy, >1020 W/cm2 intensity, sub-picosecond laser pulses on solid targets). Despite the presence of strong EMPs (beyond 100 kV/m at 1 m distance from the target), the tests were successful and the TS was able to retrieve a good-quality signal. Indeed, the close proximity to the interaction point caused a significant number of electrons, produced by the intense laser-target interaction, entering the TS and causing internal electrostatic fields up to tens of kV/m. These induced fields altered the trajectories of the detected ions, making the interpretation and characterization of the particle species not straightforward. This effect was analyzed with ad-hoc particle tracking simulations. This study is of high importance for the effective implementation of this type of high-sensitivity TSs in experiments with PW-power lasers.

Surface engineering and on-site charge neutralization for the regulation of contact electrification

Electrostatic charges can accumulate on insulator surfaces under contact electrification, resulting in hazardous conditions. Despite significant progress in eliminating charges of contact electrification, there are still several limitations, including the need to dope other materials, which can alter their original properties, and the difficulties of fabrication. Here, a new post-treatment antistatic strategy is demonstrated to significantly reduce the accumulation of static charge by controlling the spatial distribution of tribopositive and tribonegative regions. On-site interface charge neutralization between tribopositive and tribonegative regions leads to rapid charge decay, without conductive spraying or grounding, which is especially useful in some extreme scenarios, such as the aerospace industry and the electronics industry. By using this surface engineering strategy, finished materials can be easily retrofit into antistatic materials, which will open up promising possibilities for antistatic polymers in a wide range of applications.

The risk of static electricity at handling diesel fuel

Diesel fuel in motion when is transporting by pipes when is mixing, pumping, filtering, agitating or by pouring them from one vessel to another can generate static charges. Also, static electricity may occur if the liquid is splashes and forms a mist inside the tank. Accumulation of static electricity can, under certain conditions, be discharge and ignite the flammable/explosive atmosphere. Ignition hazards from static discharges can be eliminated by controlling the generation or accumulation of static charges or by eliminating a flammable mixture where static electricity may be discharged. Factors that need to be considered to reduce the risk of ignition sunt flammability characteristics of explosive atmosphere (the vapor pressure, flash point, temperature, and pressure) and the factors that determine the charging of static electricity (fuel type, electrical conductivity, sulfur content, viscosity, vehicle process: flow rate, pipe diameter, filters, pumps, spark promoters). In this paper are presented some aspects regarding the technical, organizational requirements and responsibilities of the personnel designated to prevent the formation and accumulation of static electricity when loading diesel fuel tanks, starting from a case study, respectively some explosions which occurred to a company during the loading operation.

Endowing the sustainable antistatic properties to epoxy-based composites through adding graphene nanoplatelets

In order to explore the possibility of reducing the potential hazards caused by the accumulation of static charges in electronic components, graphene nanoplatelets with remarkable conductive property were added as functional fillers into epoxy matrix to enhance the antistatic property of composites used as the encapsulating materials. Optical microscope and scanning electron microscope were used to observe the dispersion of graphene fillers in the polymer to indicate the completeness of the establishment of the conductive network. The surface of the material was charged by corona discharge method, then the decay characteristics of the static charges was continuously measured. The accumulation and decay of the static charges on the surface of the sample were systematically analyzed by combining with water contact angle, resistivity and relevant permittivity parameters. Results showed that the antistatic ability of material had been constantly enhanced with the increase of graphene content. It was worth noting that when only 0.5 wt% graphene fillers were added, the surface and volume resistivity of composite could reach 5.38 × 1012 Ω/square, 2.37 × 1010 Ω.cm respectively, fully meeting the requirement standard of antistatic encapsulating material for electronic devices. It is forecasted that the prepared composites have considerable prospects in the antistatic encapsulation of electronic devices and aerospace fields.

Reduction of electrostatic charging PETN and HMX explosives by PVP and ionic liquid

Electrostatic charges accumulate in bulk explosives during handling, producing, transferring, sieving, conveying and storage. In this study, polyvinyl pyrrolidone (PVP) polymer and ionic liquid (IL) (1-Hexyl-3-methyl imidazolium chloride [Hmim][Cl]) were added to the mixture of cyclotetramethylene-tetranitramine (HMX) and pentaerythriol tetranitrate (PETN) explosives. Then they were analyzed by the powder volumetric resistivity test and electrostatic charging test setup. The accumulation of static charge was also measured. The samples were evaluated for further studies in terms of mixing quality by FE-SEM analysis. In this work, the amount of reduction in static charge was significantly improved in the HMX and PETN samples, containing 5.5 wt% of PVP and 0.5 wt% of [Hmim][Cl] as more as 94% and 98%, respectively.

Anisotropic Triboelectric Nanogenerator Based on Ordered Electrospinning.

As a new type of energy harvesting and conversion device, nanogenerator can collect various energies from daily life environment and convert it into electrical energy; it has great flexibility and can provide power for small independent systems. The triboelectric nanogenerator (TENG) is widely concerned because of their high output energy density. However, in the case of an open circuit, there will be static charge accumulation on the friction surface. The high voltage generated by the accumulation of charge on the surface will bring the risk of electrostatic discharge (ESD) to nearby circuits. To solve this problem, we have used the ordered polymer nanofibers obtained by electrospinning technology to form an anisotropic triboelectric nanogenerator with better tensile properties and mechanical strength than disordered electrospinning TENG. By adjusting the effective contact area, the voltage output in the longitudinal direction is one order of magnitude higher than the voltage output in the lateral direction. When not in use, the nanogenerator can be rotated 90°, so static charge accumulation and circuit burnout can be avoided, providing an easy method of preventing ESD in a wearable environment.

Electromagnetic Interference Generated in a Spacecraft During Static Charge Accumulation

An approximate assessment of the electrical fields generated on charging the spacecraft is performed. The interference generated by the protecting device intended for neutralizing a noncompensated electrical charge on the spacecraft body is assessed. The assessment shows that the electrical fields can lead to failures in operations of the onboard electronic equipment.

Polymer composite for antistatic application in aerospace

Abstract The phenomenon of static electricity is unpredictable, particularly when an aircraft flying at high altitude that causes the accumulation of static charges beyond a threshold value leading to the failure of its parts and systems including severe explosion and radio communication failure. The accumulation of static charges on aircraft is generated by the virtue of interaction between the outer surface of aircraft and the external environmental attributes encompasses air particles, ice, hail, dust, volcanic ash in addition to its triboelectric charging. In the recent years, advanced polymer-based composites or nanocomposites are preferred structural constituents for aircrafts due to their light weight and comparable mechanical properties, but such composite systems do not render low impedance path for charge flow and are subsequently vulnerable to effect of lightning strike and precipitation static. In this context, it is essential to develop conductive composite systems from non-conductive polymer matrix by nanofiller embodiments. The advent of carbon-based nanocomposite/nanomaterials have adequately addressed such issues related to the nonconductive polymer matrix and further turned into an avant-garde genre of materials. The current review envisioned to illustrate the detailed exploitation of various polymer nanocomposites in addition to especially mentioned epoxy composites based on carbon fillers like carbon black, carbon nanotube (single walled carbon nanotube and multi walled carbon nanotube) and graphene the development of antistatic application in aircraft in addition to the static charge phenomenon and condition for its prevalence in avionic systems.

Electrostatic field theoretic approach to analyze the partial discharge phenomenon pertaining to insulation degradation

This paper elucidates the application of electrostatic field theory to analyze partial discharge due to the void formation inside the insulating material. Formation of voids leads to accumulation of static charges leading to capacitance build-up. The most probable cause of insulation failure is due to the subjection of high voltage. Prolonged high voltage poses a threat and leads to insulation failure. Failures occur in the tip gap between the conductor and insulating material’s inner periphery. Probable causes of such failures are corona discharge, surface discharge and treeing, leading to formation of Lichtenberger figures in the material and cavity discharge. This paper presents a way of fabricating the inner lining of the insulator with a semiconductor layer obeying avalanche breakdown at breakdown voltage or voltages at which partial discharge is likely to occur. With the onset of high voltage which can cause a discharge, the semiconductor experiences avalanche breakdown giving out a single photon ejection by Geiger mode (principle). A superior prevention method of using Teflon for insulation instead of XLPE/PILC has been suggested and simulated using COMSOL. Detection using Avalanche photo-detector(LiDAR) may enable us to track the probable location of the occurrence of partial discharge and isolate the system.

Temperature-dependent surface charge behavior of polypropylene film under DC and pulse voltages

Film capacitors are constructed with polymer films as the dielectric material, among which polypropylene (PP) has the highest breakdown strength and excellent thermal performance. Accumulation of static charge on the polymer film surface between electrode segments may induce surface discharge causing energy loss and accelerating electrical aging of insulation material in the capacitor. In the application of pulsed power systems, the capacitor faces temperature rise and multiple electrical stresses, which will influence the surface charge behavior of the polymer film. The paper is dedicated to research on the influence of temperature and different voltage waveforms on the surface charge and trap characteristics of PP film. The PP film was corona charged with needle-plate electrodes by DC voltage and combination of DC and pulse voltage, respectively, and the surface potential decay was conducted at different temperature. It is found that the rise of temperature can significantly enhance de-trapping of the surface charge in deep traps, thus accelerating the surface charge decay. Under DC voltage, the accumulation of surface charge shows no relation with temperature, while the decay is dominated by both electric field and temperature. Under multi-stress of DC and pulse voltage, however, the surface charge accumulation is influenced by temperature due to its impact on surface charge coupling. And the decay of surface charge becomes complicated with coupling process as well, in which the electrical field, trap level and density show inconsistency with the decay under different temperature.

Installations for the neutralization of granular insulating materials obtained by electrostatic separation

Preventing accumulation of static charges and finding means for its elimination have been topics of active research in the field of electrostatic separation technologies for granular mixtures of insulating mixtures. Four installations are examined as potential solutions for the neutralization of the residual charges in separation processes. The experiments are performed with mm-size granules of Acrylonitrile Butadiene Styrene (ABS) and High-Impact Polystyrene (HIPS) recovered from industrial wastes. The granules are corona charged at a potential similar to that acquired by triboelectric effect. They are spread across an electrode connected either to the ground or to a high voltage (HV) of opposite polarity, then exposed to either DC or AC corona, in view of neutralizing the residual charge. The use of AC corona gives the best results, attaining neutralization rates as high as 95.3 % for ABS and 87.3 % for HIPS granules.

정전기 방지를 위한 기능성 펄프 트레이 개발

ABSTRACT Static electricity is an imbalance of electric charges within or on the surface of a mate-rial. All packed items that are particularly sensitive to static discharge must be protected by antistatic treatment. Otherwise, static electricity generated by an electrical insulator may cause serious damages to some sensitive electronics. In order to remove or prevent a buildup of static electricity, packed items must be treated with the application of an anti-static agent, which helps any excess charge to be evenly distributed. Functional pulp tray used for packing of electronic goods was developed with application of an antistatic agent. As the concentration of the antistatic agent increased, charging voltage and surface re-sistance of molded pulps decreased. The increase of humidity in surrounding atmosphere around molded pulps led to the decrease of accumulation of static charges. In conclusion, the surface treatment of the antistatic agent not only reduced or eliminated buildup of static electricity in the surface, but also prevented generation of tiny dirts from molded tray. Keywords: Static electricity, electric charges, pulp tray, molded pulp, antistatic agent

Reflecting and Polarizing Properties of Conductive Fabrics in Ultra-High Frequency Range

The system based on ultra-wide band (UWB) signals was employed for qualitative estimation of attenuating, reflecting and polarizing properties of conductive fabrics, capable to prevent local static charge accumulation. Pulsed excitation of triangle monopole antenna of 6.5 cm height by rectangular electric pulses induced radiation of UWB signals with spectral density of power having maximum in ultra-high frequency (UHF) range. The same antenna was used for the radiated signal receiving. Filters and amplifiers of different passband were employed to divide UHF range into subranges of 0.3-0.55 GHz, 0.55-1 GHz, 1-2 GHz and 2-4 GHz bands. The free space method, when conductive fabric samples of 50x50 cm 2 were placed between transmitting and receiving antennas, was used to imitate a practical application. Received wideband signals corresponding to the defined range were detected by unbiased detectors. The fabrics made of two types of warps, containing different threads with conductive yarns, were investigated. It was estimated attenuation and reflective properties of the fabrics when electric field is collinear or perpendicular to thread direction. In the UHF range it was revealed good reflecting properties of the fabrics containing metallic component in the threads. The system has advantages but not without a certain shortcoming. Adapting it for specific tasks should lead to more effective usage, including yet unused properties of the UWB signals.

Agglomeration defects on irradiated carbon nanotubes

Aligned carbon nanotubes (CNT) were irradiated in the longitudinal and perpendicular directions, with low energy carbon and helium ions in order to observe the formation of defects in the atomic structure. Analysis through Raman spectroscopy and scanning electron microscopy indicated bundle rupture and ion track formation on nanotube bundles. Aligned CNT presented a kind of defect comprising ravine formation and tube agglomeration on top of the substrate. The latter structure is possibly caused by static charge accumulation induced by the incoming ions. Fluence plays a role on the short range order. Higher fluence irradiation transforms CNT into amorphous carbon nanowires.