Zeitschriftenartikel
  • Wang, J.
  • Dmitry Rychkov
  • Gerhard, R.
Space–charge electret properties of polypropylene films with transcrystalline or spherulitic structures—A comparison of functionalities at interfaces, vol. 129, pg. 064101.

In: Journal of Applied Physics

  • 2021

DOI: 10.1063/5.0039867

Spherulite-related space–charge electret properties of polypropylene (PP) have been widely discussed in the past decades. In the present paper, a less-common crystalline structure in PP—transcrystalline PP—is studied regarding its electret behavior in comparison with the typical spherulitic morphology. Polarized light microscopy and differential scanning calorimetry were employed to characterize the crystallite types and crystallinities of transcrystalline and spherulitic PP. Their electret functionality is investigated by means of thermally stimulated discharge experiments, where the cross-over phenomenon is observed on transcrystalline PP films, whereas surface-potential saturation and undercharging on the surface occur on the spherulitic samples. Besides, an asymmetrical behavior of positive and negative surface-charge stabilities is found on PP with spherulites, the negatively charged spherulitic surfaces show a better charge stability. It is shown that PP electrets are very sensitive to changes in the microscopic crystalline structures and their interfaces as well as in the molecular conformations controlled through adjustments of the respective processing steps. In addition, surface and bulk nanocomposites of PP or low-density polyethylene with inorganic particles are included in the comparison. In view of recent developments in the areas of PP-based electret-fiber filters and cellular-foam ferroelectrets, the observed changes in the charge-storage properties may have particular relevance, as the required film, fiber, or foam processing might significantly modify crystalline morphologies and nano-scale interfaces in PP electrets. Limitations in the charge-storage capabilities of interface structures may also be of interest in the context of high-voltage electrical-insulation materials where reduced space–charge accumulation and slightly increased charge transport can be advantageous.
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Zeitschriftenartikel
  • Wang, J.
  • Dmitry Rychkov
  • Q. Nguyen
  • Gerhard, R.
The influence of orthophosphoric-acid surface modification on charge-storage enhancement in polypropylene electrets, vol. 128, pg. 034102.

In: Journal of Applied Physics

  • 2020

DOI: 10.1063/5.0013805

Bipolar electrets from polypropylene (PP) are essential, e.g., in electret air filters and in cellular-foam ferroelectrets. Therefore, the mechanism of surface-charge stability enhancement on PP electrets via orthophosphoric-acid surface treatment is investigated in detail. It is shown that the significant charge-stability enhancement can be mainly attributed to deeper surface traps originating from deposited chemicals and topographic features on the modified surfaces. Thermally stimulated discharge of chemically treated and non-treated PP films with different surface-charge densities is used to test the limits of the newly formed deep traps in terms of the capacity for hosting surface charges. When the initial surface-charge density is very high, more charges are forced into shallower original traps on the surface or in the bulk of the treated PP samples, reducing the effect of the deeper surface traps brought by the surface modification. The well-known crossover phenomenon (of the surface-charge decay curves) has been observed between modified PP electrets charged to ±2 kV and to ±3  kV. Acoustically probed charge distributions in the thickness direction of PP electrets at different stages of thermal discharging indicate that the deep surface trapping sites may have preference for negative charges, resulting in the observed asymmetric charge stability of the modified PP films.
  • TSZ Weißenburg
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Zeitschriftenartikel
  • Wang, J.
  • Dmitry Rychkov
  • Q. Nguyen
  • Gerhard, R.
Unexpected bipolar space-charge polarization across transcrystalline interfaces in polypropylene electret films, vol. 128, pg. 134103.

In: Journal of Applied Physics

  • 2020

DOI: 10.1063/5.0022071

A double-layer transcrystalline polypropylene (PP) film with a flat central interface layer between its two transcrystalline layers is obtained by recrystallization from the melt between two polytetrafluoroethylene (PTFE) surfaces on both sides of the PP film. Its electret properties are studied and compared with those of a single-layer transcrystalline PP film re-crystallized in contact with only one PTFE surface. Within experimental uncertainty, the two types of transcrystalline films exhibit the same thermal properties and crystallinities. After thermal poling, however, two hetero-charge layers of opposite polarity are found on the internal interfaces of the double-layer transcrystalline films and may together be considered as micrometer-sized dipoles. The unexpected phenomenon does not occur in single-layer transcrystalline samples without a central interface layer, suggesting that the interfaces between the transcrystalline layers and the micrometer-thick central interface layer may be the origin of deeper traps rather than the crystalline structures in the transcrystallites or the spherulites. The origin of the interfacial charges was also studied by means of an injection-blocking charging method, which revealed that intrinsic charge carriers introduced during recrystallization are most likely responsible for the interfacial charges. It is fascinating that a material as familiar as PP can exhibit such intriguing properties with a special bipolar space-charge polarization across the central interface layer after quasi-epitaxial surface moulding into a double-layer transcrystalline form. In addition to applications in electret (micro-)devices for electro-mechanical transduction, the highly ordered structures may also be employed as a new paradigm for studying charge storage and transport in polymer electrets and in dielectrics for DC electrical insulation.
  • TSZ Weißenburg
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Zeitschriftenartikel
  • Y.A.O. Assagra
  • Altafim, R.A.P.
  • J. do Carmo
  • R.A.C. Altafim
  • Dmitry Rychkov
  • Wirges, W.
  • Gerhard, R.
A new route to piezo-polymer transducers: 3D printing of polypropylene ferroelectrets, vol. 27, pg. 1668-1674.

In: IEEE Transactions on Dielectrics and Electrical Insulation

  • 2020

DOI: 10.1109/TDEI.2020.008461

Here, a promising approach for producing piezo-polymer transducers in a one-step process is presented. Using 3D-printing technology and polypropylene (PP) filaments, we are able to print a two-layered film structure with regular cavities of precisely controlled size and shape. It is found that the 3D-printed samples exhibit piezoelectric coefficients up to 200 pC/N, similar to those of other PP ferroelectrets, and their temporal and thermal behavior is in good agreement with those known of PP ferroelectrets. The piezoelectric response strongly decreases for applied pressures above 20 kPa, as the pressure in the air-filled cavities strongly influences the overall elastic modulus of ferroelectrets.
  • TSZ Weißenburg
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Beitrag (Sammelband oder Tagungsband)
  • Q. Nguyen
  • Wang, J.
  • Dmitry Rychkov
  • Gerhard, R.
Depth Profile and Transport of Positive and Negative Charge in Surface (2-D) and Bulk (3-D) Nanocomposite Films, pg. 298-300.
  • 2019

DOI: 10.1109/ICEMPE.2019.8727256

In the present study, the charge distribution and the charge transport across the thickness of 2- and 3-dimensional polymer nanodielectrics was investigated. Chemically surface-treated polypropylene (PP) films and low-density polyethylene nanocomposite films with 3 wt % of magnesium oxide (LDPE/MgO) served as examples of 2-D and 3-D nanodielectrics, respectively. Surface charges were deposited onto the non-metallized surfaces of the one-side metallized polymer films and found to broaden and to thus enter the bulk of the films upon thermal stimulation at suitable elevated temperatures. The resulting space-charge profiles in the thickness direction were probed by means of Piezoelectrically-generated Pressure Steps (PPSs). It was observed that the chemical surface treatment of PP which led to the formation of nano-structures or the use of bulk nanoparticles from LDPE/MgO nanocomposites enhance charge trapping on or in the respective polymer films and also reduce charge transport inside the respective samples.
  • TSZ Weißenburg
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Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
Controlling Trapping Parameters via Polymer Structure and Composition? (Keynote), pg. 22.
  • 2019
Space-charge electrets are usually fabricated from non-polar polymers. Such materials as polyethylene, polypropylene, polytetrafluoroethylene and its copolymers are used in electret microphones, filters, radiation dosimeters, and different kinds of electromechanical transducers, as well as in biomedical devices [1]. The key factor in all these applications is both thermal and temporal stability of the electret charge. However, the existing materials do not always possess the required level of charge stability. Or, on the other hand, a material may be an excellent electret, but lack in processability, cost efficiency etc. In general, there is a need to be able to control electret properties of commercially available polymer materials used in various electroactive applications. Here we will discuss how changes in chemical composition and structural changes can influence electret charge storage and transport in non-polar polymers.
  • TSZ Weißenburg
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Beitrag (Sammelband oder Tagungsband)
  • Rychkov, A. A.
  • V. Stojharov
  • Kuznetsov, A.
  • Dmitry Rychkov
The Influence of Recrystallization Regimes on Electret Charge Stability in Low-Density Polyethylene Films, pg. 740-743.
  • 2018
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Zeitschriftenartikel
  • Dmitry Rychkov
  • Altafim, R.A.P.
Template-based fluoroethylenepropylene ferroelectrets with enhanced thermal stability of piezoelectricity, vol. 124, pg. 174105.

In: Journal of Applied Physics

  • 2018

DOI: 10.1063/1.5041374

In ferroelectrets, the piezoelectricity stems from the charges of both polarities trapped on the inner surfaces of the cavities in the material, so that its thermal stability is defined by the stability of the respective charges. In the present work, a template-based lamination technique has been employed to fabricate tubular-channel ferroelectrets from fluoroethylenepropylene (FEP) films. It has been shown that the piezoelectricity in FEP ferroelectrets decays at relatively low temperatures due to the inherently lower thermal stability of the positive charge. In order to improve charge trapping, we have treated both FEP films and inner surfaces of the ferroelectret cavities with titanium-tetrachloride vapor, using the atomic-layer-deposition technique. Using surface-potential-decay measurements on FEP films, we have found that the charge-decay curves shift by more than 100 ∘C to the higher temperatures as a result of the surface treatment. Direct measurements of piezoelectric d33 coefficients as a function of temperature have shown that the piezoelectric stability is likewise improved with the d33-decay curves shifted by 60 ∘C to the right. The improvement of electret/ferroelectret properties can be attributed to the formation of the deeper traps on the chemically modified FEP surface. SEM micrographs and EDS analysis reveal island-like structures with titanium- and oxygen-containing species that can be responsible for the deeper trapping of the electret charges.
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Wang, J.
  • Dmitry Rychkov
  • Gerhard, R.
Influence of Charge Density on Charge Decay in Chemically Modified Polypropylene Films, pg. 549-552.
  • 2018
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Zeitschriftenartikel
  • Dmitry Rychkov
  • Gerhard, R.
  • Kuznetsov, A.
  • Rychkov, A. A.
Influence of Charge Density on the Trap-Energy Spectrum in Fluoroethylenepropylene Copolymer Films with Chemically Modified Surfaces, vol. 25, pg. 840-844.

In: IEEE Transactions on Dielectrics and Electrical Insulation

  • 2018

DOI: 10.1109/TDEI.2018.007437

Tetrafluoroethylene-hexafluoropropylene copolymer (FEP) films were treated with titanium-tetrachloride vapor by means of molecular-layer deposition. The treatment leads to considerable improvements of the electret-charge stability on positively charged films. A slight improvement is also observed for negatively charged films. In line with our previous findings, we attribute the improvement in electret properties to the formation of deeper traps on the chemically modified polymer surfaces. Here, we investigate the influence of the charge density on electret stability of FEP films with modified surfaces. Trap-energy spectra obtained from thermally-stimulated-discharge measurements indicate that the charge stability on modified FEP films depends on how the surface traps are populated and on the availability of additional deeper traps.
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • F. He
  • Wang, J.
  • Dmitry Rychkov
  • Schulze, M.
  • Wirges, W.
  • Gerhard, R.
Senskin deformable silicone-elastomer sensors for structural health monitoring: assessment of strain sensitivity and correction for thermal expansion
  • 2018
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • F. He
  • Wang, J.
  • Schulze, M.
  • G. Gidion
  • Wirges, W.
  • Gerhard, R.
Soft Stretchable All-Silicone Sensor for Transport-Infrastructure Monitoring
  • 2018
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Zeitschriftenartikel
  • Cheilakou, E.
  • Tsopelas, N.
  • Anastasopoulos, A.
  • Kourousis, D.
  • Dmitry Rychkov
  • Gerhard, R.
  • Frankenstein, B.
  • Amditis, A.
  • Damigos, Y.
  • Bouklas, C.
Strain monitoring system for steel and concrete structures, vol. 10, pg. 25-32.

In: Procedia Structural Integrity

  • 2018

DOI: 10.1016/j.prostr.2018.09.005

The present work is part of a collaborative H2020 European funded research project called SENSKIN, that aims to improve Structural Health Monitoring (SHM) for transport infrastructure through the development of an innovative monitoring and management system for bridges based on a novel, inexpensive, skin-like sensor. The integrated SENSKIN technology will be implemented in the case of steel and concrete bridges, and tested, field-evaluated and benchmarked on actual bridge environment against a conventional health monitoring solution developed by Mistras Group Hellas. The main objective of the present work is to implement the autonomous, fully functional strain monitoring system based on commercially available off-the-shelf components, that will be used to accomplish direct comparison between the performance of the innovative SENSKIN sensors and the conventional strain sensors commonly used for structural monitoring of bridges. For this purpose, the mini Structural Monitoring System (mini SMS) of Physical Acoustics Corporation, a comprehensive data acquisition unit designed specifically for long-term unattended operation in outdoor environments, was selected. For the completion of the conventional system, appropriate foil-type strain sensors were selected, driven by special conditioners manufactured by Mistras Group. A comprehensive description of the strain monitoring system and its peripheral components is provided in this paper. For the evaluation of the integrated system’s performance and the effect of various parameters on the long-term behavior of sensors, several test steel pieces instrumented with different strain sensors configurations were prepared and tested in both laboratory and field ambient conditions. Furthermore, loading tests were performed aiming to validate the response of the system in monitoring the strains developed in steel beam elements subject to bending regimes. Representative results obtained from the above experimental tests have been included in this paper as well.
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Wirges, W.
  • Qiu, X.
  • Dmitry Rychkov
  • Gerhard, R.
Pressure dependence of the piezoelectric d33 coefficient and the cellular-foam structure in polypropylene ferro- and piezoelectrets
  • 2017
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Wang, J.
  • Dmitry Rychkov
  • Gerhard, R.
Influence of foreign chemical structures from nitric acid treatment on electret and electrical-insulation properties of polypropylene
  • 2017
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • Gerhard, R.
  • Kuznetsov, A.
  • Rychkov, A. A.
Trap-energy spectrum in corona-charged polytetrafluoroethylene (PTFE) electret films with modified surfaces
  • 2017
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Q. Nguyen
  • Wang, J.
  • Dmitry Rychkov
  • Gerhard, R.
Piezoelectrically generated Pressure Steps (PPS) for studying charge distributions on corona-charged Polypropylene (PP) films
  • 2017
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • Schulze, M.
  • Gerhard, R.
Soft Capacitive Sensors for Structural Health Monitoring, pg. 311-313.
  • 2017
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Zeitschriftenartikel
  • Loupos, K.
  • Damigos, Y.
  • Amditis, A.
  • Gerhard, R.
  • Dmitry Rychkov
  • Wirges, W.
  • Schulze, M.
  • Lenas, S.-A.
  • Chatziandreoglou, C.
  • Malliou, C.M.
  • Tsaoussidis, V.
  • Brady, K.
  • Frankenstein, B.
Structural health monitoring system for bridges based on skin-like sensor, vol. 236, pg. 012100.

In: IOP Conference Series: Materials Science and Engineering

  • 2017

DOI: 10.1088/1757-899X/236/1/012100

Structural health monitoring activities are of primal importance for managing transport infrastructure, however most SHM methodologies are based on point-based sensors that have limitations in terms of their spatial positioning requirements, cost of development and measurement range. This paper describes the progress on the SENSKIN EC project whose objective is to develop a dielectric-elastomer and micro-electronics-based sensor, formed from a large highly extensible capacitance sensing membrane supported by advanced microelectronic circuitry, for monitoring transport infrastructure bridges. Such a sensor could provide spatial measurements of strain in excess of 10%. The actual sensor along with the data acquisition module, the communication module and power electronics are all integrated into a compact unit, the SENSKIN device, which is energy-efficient, requires simple signal processing and it is easy to install over various surface types. In terms of communication, SENSKIN devices interact with each other to form the SENSKIN system; a fully distributed and autonomous wireless sensor network that is able to self-monitor. SENSKIN system utilizes Delay-/Disruption-Tolerant Networking technologies to ensure that the strain measurements will be received by the base station even under extreme conditions where normal communications are disrupted. This paper describes the architecture of the SENSKIN system and the development and testing of the first SENSKIN prototype sensor, the data acquisition system, and the communication system.
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Zeitschriftenartikel
  • Wang, J.
  • Dmitry Rychkov
  • Gerhard, R.
Chemical modification with orthophosphoric acid enhances surface-charge stability on polypropylene electrets, vol. 110, pg. 192901.

In: Applied Physics Letters

  • 2017

DOI: 10.1063/1.4983348

The low surface-charge stability of polypropylene (PP) frequently limits its application as an electret material. In this paper, we demonstrate how the treatment of PP-film surfaces with orthophosphoric acid (H3PO4) enhances their charge stability. To discriminate between the effects of chemical modification and thermal treatment, as-received and annealed PP films are used as reference samples. The electret properties of treated and non-treated PP films are characterized with thermally stimulated discharge (TSD) and isothermal surface-potential decay (ISPD) experiments, from which considerable improvement in thermal and temporal charge stability is observed for samples modified with H3PO4. The half-value temperature (T1∕2) observed on TSD curves of chemically treated PP increases to 131 and 145 °C for positive and negative charges, respectively. The enhancement might be attributed to the phosphoric compounds detected on the H3PO4-modified surfaces via attenuated-total-reflection infrared spectroscopy. Deeper surface traps formed at the “foreign” phosphorus-containing structures are able to capture the charges over longer time periods and at higher temperatures, thus leading to significant improvements in the temporal and thermal surface-charge stabilities of PP electrets.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • Gerhard, R.
  • Kuznetsov, A.
  • Rychkov, A. A.
Energy Spectrum of Surface Traps on Teflon-FEP Films Modified with Titanium-Tetrachloride Vapor, pg. 169-171.
  • 2016
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • Gerhard, R.
  • Kuznetsov, A.
  • Rychkov, A. A.
Modelling the Isothermal Charge Decay of Modified PTFE Electrets from their Thermally Stimulated Discharge, pg. 105-108.
  • 2016
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Wang, J.
  • Dmitry Rychkov
  • Gerhard, R.
Influence of surface modifications with orthophosphoric acid on the charge stability of polypropylene electrets, pg. 78-80.
  • 2016
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • Altafim, R.A.P.
Polymer Electrets and Ferroelectrets as EAPs: Models" Book chapter in "Electromechanically Active Polymers", pg. 1-15.

In: Electromechanically Active Polymers. A Concise Reference (Polymers and Polymeric Composites: A Reference Series)

  • 2016
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Loupos, K.
  • Amditis, A.
  • A. Tsertou
  • Damigos, Y.
  • Gerhard, R.
  • Dmitry Rychkov
  • Wirges, W.
  • V. Kalidromitis
  • S. Camarinopoulos
  • S. Lenas
  • V. Tsaoussidisa
  • Anastasopoulos, A.
  • K. Lenz
  • S. Schneider
  • M. Hill
  • A. Adesiyun
  • Frankenstein, B.
Skin-like Sensor Enabled Bridge Structural Health Monitoring System
  • 2016
Structural Health Monitoring (SHM) has an important role in the management of transport infrastructure. However, most SHM techniques are based on data obtained from dense networks of point-based sensors (rather than sparse networks of spatial sensors) and so, inrelative terms, they are costly to implement. Most commercially available strain sensors have a limited maximum range - typically 1% to 2% - and are not well-suited to providing information of a severe loss of structural integrity. The SENSKIN project develops a dielectric-elastomer and micro-electronics-based skin-like sensor, based on the use of a largehighly extensible capacitance sensing membrane and advanced micro-electronic circuitry, for monitoring transport infrastructure - such as bridges. The sensor will provide spatial measurements of strain of more than 10% and is being designed to (a) require low power to operate, (b) be easy to install (c) have a comparable or lower cost than conventional strain sensors, (d) allow simple signal processing, and (e) have the ability to self-monitor and self-report. The system will support the new and emerging technology of Delay/Disruption-Tolerant Networking to secure that strain measurements acquired will reach the base station even under extreme conditions where communications may be disrupted. SENSKIN also develops a Decision-Support-System (DSS) for proactive condition-based structural interventions under normal operating conditions and reactive emergency intervention following an extreme event. In assessing potential rehabilitation options, the DSS will use the data supplied by the SENSKIN sensors together with advanced structural analysis models, whilst taking account of the lifecycle economic, social and environmental implications. The overall monitoring system will be evaluated and benchmarked on actual bridges of Egnatia Highway (Greece) and Bosporus Bridge (Turkey). This paper describes the concept and principles of the SENSKIN sensing system, and its various components with attention to end-user requirements, specifications and system architecture.
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • Wirges, W.
  • Gerhard, R.
  • Altafim, R.A.P.
Unipolar Teflon -FEP Ferroelectrets – Choice of Negative Electret Charge Enhances Stability, pg. 84-86.
  • 2015
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Patent
  • Gerhard, R.
  • Dmitry Rychkov
  • Wirges, W.
  • et al.
Electromechanical transducer device for use in e.g. actuator device, has electret material having predetermined electrical charge, which is provided between electro-active layers
  • 2015
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Qiu, X.
  • Dmitry Rychkov
  • Wirges, W.
Properties and Applications of Ferroelectrets, pg. 271-285.
  • 2015
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • Gerhard, R.
  • Ivanov, V.
  • Kuznetsov, A.
  • Rychkov, A. A.
Rubbing Treatment before Chemical Surface Modification Enhances Deep Trapping of Positive Charge on Polytetrafluoroethylene (PTFE) Electrets, pg. 87-89.
  • 2015
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Patent
  • N. Efimov
  • V. Ivanov
  • A. Kuznetsov
  • Dmitry Rychkov
  • et al.
Method of film electret production, involves application of fluoropolymer layer onto metal electrode and discrete layer consisting of isolated nano-sized aggregates out of titan-containing nanostructures onto fluoropolymer surface
  • 2014
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
Stabilization of Electric Charges on Self-Organized Nano-Islands
  • 2014
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Rychkov, A. A.
  • Kuznetsov, A.
  • Dmitry Rychkov
  • Ivanov, V.
Thermal stability of negative homocharge in tetrafluoroethylene-hexafluoropropylene copolymer films. (in Russian), pg. 193-195.
  • 2014
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • M. Khorasani
  • M. Kollosche
  • Wirges, W.
  • Gerhard, R.
The Influence of Carbon-Nanotube Electrodes on the Charge Decay in Silicone-Elastomer Films for Electro-Electret Applications
  • 2014
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • Ivanov, V.
  • Rychkov, A. A.
  • Gerhard, R.
Enhanced Stability of Negative Charge on FEP-Copolymer Electrets Treated with TiCl4 Vapor: Voltage-Recovery Experiment
  • 2014
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • Altafim, R.A.P.
  • Efimov, N.
  • Gerhard, R.
Improved thermal stability of FEP ferroelectrets through inner voids surface modification, pg. 160-162.
  • 2014
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • Altafim, R.A.P.
  • Gerhard, R.
Unipolar ferroelectrets - Following the example of the electret microphone more closely, pg. 860-862.
  • 2014
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Patent
  • Efimov, N.
  • Y. Julenets
  • A. Kuznetsov
  • Dmitry Rychkov
  • et al.
Method of film electret production involves application of fluoropolymer layer onto metal electrode
  • 2014
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Zeitschriftenartikel
  • Dmitry Rychkov
  • Kuznetsov, A.
  • Rychkov, A. A.
Thermally Stimulated Electret Surface Potential Recovery in Polyethylene Films Modified in Phosphorus Trichloride Vapor. (in Russian), vol. 157, pg. 113-118.

In: Izvestiya RGPU: Scientific Journal

  • 2013
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Buch (Monographie)
  • Dmitry Rychkov
  • Kuznetsov, A.
  • Rychkov, A. A.
СТАБИЛИЗАЦИЯ ЗАРЯДА ПОЛИМЕРНЫХ ЭЛЕКТРЕТОВ (Charge stabilization in polymer electrets). A textbook for Engineering or Physics bachelor/master students
  • 2013
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Zeitschriftenartikel
  • Dmitry Rychkov
  • Rychkov, A. A.
  • Efimov, N.
  • A. Malygin
  • Gerhard, R.
Higher stabilities of positive and negative charge on tetrafluoroethylene–hexafluoropropylene copolymer (FEP) electrets treated with titanium-tetrachloride vapor, vol. 112, pg. 283-287.

In: Applied Physics A - Materials Science and Processing

  • 2013

DOI: 10.1007/s00339-013-7821-1

Tetrafluoroethylene–hexafluoropropylene copolymer (FEP) films were treated with titanium-tetrachloride vapor in a molecular-layer deposition process. As a result of the surface treatment, significant improvements of the thermal and temporal charge stability were observed. Charge-decay measurements revealed enhancements of the half-value temperatures and the relaxation times of positively charged FEP electrets by at least 120 °C and two orders of magnitude, respectively. Beyond previous publications on fluoropolymer electrets with surface modification, we here report enhanced charge stabilities of the FEP films charged in negative as well as in positive corona discharges. Even though the improvement for negatively charged FEP films is moderate (half-value temperature about 20 °C higher), our experiments show that the asymmetry in positive and negative charge stability that is typical for FEP electrets can be overcome by means of chemical surface treatments. The results are discussed in the context of the formation of modified surface layers with enhanced charge-trapping properties.
  • TSZ Weißenburg
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Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • Wirges, W.
  • Gerhard, R.
  • Rychkov, A. A.
  • A. Malygin
  • Efimov, N.
Stabilization of Positive Charge on FEP Electret Films Modified with Titanium-Tetrachloride Vapor: Formation of a Two-Dimensional Nanodielectric?, pg. 374-376.
  • 2013

DOI: 10.1109/ICSD.2013.6619860

It has been shown recently that the stability of positively corona-charged polytetrafluoroethylene (PTFE) electrets is considerably enhanced as a result of a surface treatment with titanium-tetrachloride (TiCl 4 ) vapor. In the present study, we investigate the influence of a gas-phase treatment with TiCl 4 on the electret properties of tetrafluoroethylene-hexafluoropropylene copolymer (FEP) films. FEP-film samples were treated with titanium-tetrachloride vapor by means of a nanotechnological chemical process that is based on molecular-layer deposition. Subsequently, the samples were poled in a positive corona discharge at room temperature. A very significant improvement of the surface-charge stability has been observed on the modified FEP films. The phenomenon is not restricted to the thermal stability of the surface charge, but is also found in long-term charge-decay measurements. Typical relaxation times for positive charge under isothermal conditions are at least one order of magnitude higher after the surface modification. Thermally-stimulated-decay data indicate that the half-value temperatures of the vapor-treated samples have been enhanced to almost 200°C. Thus, the thermal stability of positive charge in modified FEP films may reach values that were so far only obtained on negatively charged FEP electrets. The results are discussed in connection with the formation of deep traps on the chemically modified polymer surfaces and in the context of two-dimensional surface-layer nanodielectrics.
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Zeitschriftenartikel
  • McCarthy, D.N.
  • H. Stoyanov
  • Dmitry Rychkov
  • H. Ragusch
  • M. Melzer
  • G. Kofod
Increased permittivity nanocomposite dielectrics by controlled interfacial interactions, vol. 72, pg. 731-736.

In: Composites Science and Technology

  • 2012

DOI: 10.1016/j.compscitech.2012.01.026

The use of nanoparticles in polymer composite dielectrics has promised great improvements, but useful results have been elusive. Here, the importance of the interfacial interactions between the nanoparticles and the polymer matrix are investigated in TiO2 nanocomposites for dielectric materials using surface functionalisation. The interface is observed to dominate the nanocomposite properties and leads to a threefold increase in permittivity at volume fractions as low as 10%. Surface functionalisation of the filler nanoparticles with silanes allows control of this interface, avoiding significant degradation of the other important material properties, particularly electrical breakdown strength, and resulting in a material that is demonstrated successfully as an active material in a dielectric elastomer actuator application with increased work output compared to the pure polymer. Although further permittivity increases are observed when the interface regions have formed a percolation network, the other material properties deteriorate. The observation of percolation behaviour allows the interface thickness to be estimated.
  • TSZ Weißenburg
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Zeitschriftenartikel
  • Altafim, R.A.P.
  • Dmitry Rychkov
  • Wirges, W.
  • Gerhard, R.
  • Basso, H.C.
  • R.A.C. Altafim
  • M. Melzer
Laminated tubular-channel ferroelectret systems from low-density polyethylene films and from fluoroethylene-propylene copolymer films-A comparison, vol. 19, pg. 1116-1123.

In: IEEE Transactions on Dielectrics and Electrical Insulation

  • 2012

DOI: 10.1109/TDEI.2012.6259978

  • TSZ Weißenburg
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  • NACHHALTIG
Zeitschriftenartikel
  • Dmitry Rychkov
  • Altafim, R.A.P.
  • Qiu, X.
  • Gerhard, R.
Treatment with orthophosphoric acid enhances the thermal stability of the piezoelectricity in low-density polyethylene ferroelectrets, vol. 111, pg. 124105.

In: Journal of Applied Physics

  • 2012

DOI: 10.1063/1.4729866

Ferroelectrets have been fabricated from low-density polyethylene (LDPE) films by means of a template-based lamination. The temperature dependence of the piezoelectric d33 coefficient has been investigated. It was found that low-density polyethylene ferroelectrets have rather low thermal stability with the piezoelectric coefficient decaying almost to zero already at 100 °C. This behavior is attributed to the poor electret properties of the polyethylene films used for the fabrication of the ferroelectrets. In order to improve the charge trapping and the thermal stability of electret charge and piezoelectricity, LDPE ferroelectrets were treated with orthophosphoric acid. The treatment resulted in considerable improvements of the charge stability in LDPE films and in ferroelectret systems made from them. For example, the charge and piezoelectric-coefficient decay curves shifted to higher temperatures by 60 K and 40 K, respectively. It is shown that the decay of the piezoelectric coefficient in LDPE ferroelectrets is governed by the relaxation of less stable positive charges. The treatment also leads to noticeable changes in the chemical composition of the LDPE surface. Infrared spectroscopy reveals absorption bands attributed to phosphorus-containing structures, while scanning electron microscopy shows new island-like structures, 50–200 nm in diameter, on the modified surface.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • Wirges, W.
  • Gerhard, R.
  • Rychkov, A. A.
Triboelectrification and Thermal Stability of Positive Charge on Polytetrafluoroethylene Electret Films, pg. 658-660.
  • 2012
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Patent
  • Rychkov, A. A.
  • Dmitry Rychkov
  • Dergachev, V.F.
  • et al.
Method of film electret production, involves applying fluoropolymer layer on metal electrode surface with electreting and applying discrete layer on fluoropolymer surface with nanosized aggregates of titan-containing nanostructures
  • 2012
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Zeitschriftenartikel
  • Dmitry Rychkov
  • Yablokov, M.
  • Rychkov, A. A.
Chemical and physical surface modification of PTFE films—an approach to produce stable electrets, vol. 107, pg. 589-596.

In: Applied Physics A - Materials Science and Processing

  • 2012

DOI: 10.1007/s00339-012-6834-5

The thermal stability of positive charge has been investigated in chemically and physically treated polytetrafluoroethylene (PTFE) films. It has been found that virgin films, oriented by the manufacturer, display an increase in thermal stability of positive charge with an increase of the initial value of surface potential. Such an anomalous behavior is explained by the influence of a negative tribocharge, trapped some small distance below the surface. In PTFE samples treated with orthophosphoric acid and with tetraethoxysilane, a considerable improvement of positive charge stability has been achieved, but no influence of the initial value of surface potential has been observed. However, this influence should be kept in mind when comparing charge stability in virgin and modified samples. In nonoriented PTFE films, no influence of the initial value of surface potential on charge stability has been observed. This could be due to the fact that these films did not possess a noticeable negative tribocharge. After the treatment in glow-discharge defluorination, oxidation and appearance of polar groups have been detected on the surface. These changes in chemical composition of a PTFE surface resulted in a noticeable improvement in thermal stability of positively charged electrets. This improvement is attributed to the formation of deeper traps on the modified surface.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
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Zeitschriftenartikel
  • Dmitry Rychkov
  • Gerhard, R.
  • Ivanov, V.
  • Rychkov, A. A.
Enhanced electret charge stability on polyethylene films treated with titanium-tetrachloride vapor, vol. 19, pg. 1305-1311.

In: IEEE Transactions on Dielectrics and Electrical Insulation

  • 2012

DOI: 10.1109/TDEI.2012.6260005

Low-density polyethylene (LDPE) films have been treated with titanium-tetrachloride vapor by means of the molecular-layer-deposition method. It is shown that such a treatment leads to a considerable improvement of the electret properties for both positively and negatively charged films. The temperature stability of the electret homo-charge has been increased by approximately 60°C. At the same time, the temporal stability of charge is also considerably improved. Modified low-density polyethylene films show no “cross-over phenomenon” when charged to higher voltages. Thus, it is now possible to produce electrets from polyethylene films with high initial charge densities, but without a strongly reduced charge stability. The influence of a chemical treatment with titanium-tetrachloride vapor on charge injection from aluminum electrodes into polyethylene films was also investigated. It is found that the interface between an aluminum electrode and a modified LDPE surface layer has different injection properties for positive and negative charges. Electrons can be injected across the modified interface, whereas injection of holes is either very limited or non-existent.
  • TSZ Weißenburg
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  • NACHHALTIG
Zeitschriftenartikel
  • Dmitry Rychkov
  • Gerhard, R.
Stabilization of positive charge on polytetrafluoroethylene electret films treated with titanium-tetrachloride vapor, vol. 98, pg. 122901.

In: Applied Physics Letters

  • 2011

DOI: 10.1063/1.3565166

The surface of polytetrafluoroethylene films was treated with titanium-tetrachloride vapor. The treatment was carried out in a flow reactor by means of molecular-layer deposition, a method from the arsenal of chemical nanotechnology. X-ray photoelectron spectroscopy reveals that such a treatment results in considerable changes in the chemical composition at and near the surface of the fluoropolymer film. Both, defluorination and oxidation of the surface were observed. At the same time, samples treated with titanium tetrachloride show a significant enhancement in the thermal stability of the positive homocharge. The thermally stimulated surface-potential-decay curves were observed to shift to higher temperatures by more than 100 °C The authors are indebted to Dr. Andreas Holländer (Fraunhofer Institute for Applied Polymer Research, Potsdam-Golm, Germany) for making the XPS measurements possible and to Dr. Sergey Trifonov of St. Petersburg State Institute of Technology (St. Petetrsburg, Russia) for the treatment of PTFE films with titanium-tetrachloride vapor.
  • TSZ Weißenburg
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Beitrag (Sammelband oder Tagungsband)
  • G. Kofod
  • H. Stoyanov
  • M. Kollosche
  • S. Risse
  • H. Ragusch
  • D. McCarthy
  • R. Wache
  • Dmitry Rychkov
  • M. Dansachmüller
Molecular level materials design for improvements of actuation properties of dielectric elastomer actuators, pg. 79760J.
  • 2011

DOI: 10.1117/12.880981

Dielectric elastomer actuators are soft electro-mechanical transducers with possible uses in robotic, orthopaedic and automotive applications. The active material must be soft and have a high ability to store electrical energy. Hence, three properties of the elastic medium in a dielectric elastomer actuator affect the actuation properties directly: dielectric constant, electric breakdown strength, and mechanical stiffness. The dielectric constant of a given elastomer can be improved by mixing it with other components with a higher dielectric constant, which can be classified as insulating or conducting. In this paper, an overview of all approaches proposed so far for dielectric constant improvement in these soft materials will be provided. Insulating particles such as TiO2 nanoparticles can raise the dielectric constant, but may also lead to stiffening of the composite, such that the overall actuation is lowered. It is shown here how a chemical coating of the TiO2 nanoparticles leads to verifiable improvements. Conducting material can also lead to improvements, as has been shown in several cases. Simple percolation, relying on the random distribution of conducting nanoparticles, commonly leads to drastic lowering of the breakdown strength. On the other hand, conducting polymer can also be employed, as has been demonstrated. We show here how an approach based on a specific chemical reaction between the conducting polymer and the elastomer network molecules solves the problem of premature breakdown which is otherwise typically found.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
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Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • A. Kuznetsov
  • Rychkov, A. A.
  • V. Goldade
Electret Properties of Polyethylene Films Modified with Titanium Tetrachloride Vapor, pg. 113-114.
  • 2011

DOI: 10.1109/ISE.2011.6085007

Low density polyethylene films have been treated with titanium tetrachloride vapor by means of the molecular layer deposition method. It has been shown that such a treatment leads to a considerable improvement of the electret properties. The thermal stability of the electret homocharge has been increased by 60°C. At the same time, the temporal stability of charge is also improved. The modified low density polyethylene films show no “crossover phenomenon” when charged to higher voltages. Thus it is now possible to produce electrets from polyethylene films with high values of the initial charge density without a detrimental influence on the charge stability.
  • TSZ Weißenburg
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Zeitschriftenartikel
  • Dmitry Rychkov
  • Kuznetsov, A.
  • Rychkov, A. A.
Electret Properties of Polyethylene and Polytetrafluoroethylene Films with Chemically Modified Surface, vol. 18, pg. 8-14.

In: IEEE Transactions on Dielectrics and Electrical Insulation

  • 2011

DOI: 10.1109/TDEI.2011.5704487

This paper investigates the effect of chemical surface modification of polytetrafluoroethylene (PTFE) and low density polyethylene (LDPE) films on their electret properties. PTFE films were subjected to wet treatment with three different chemicals: orthophosphoric acid, tetrabutyl titanate and tetraethoxysilane. The technique based on the principles of molecular layer deposition (MLD) method was used to modify the surface of LDPE films with phosphorus trichloride vapors. The surfaces of the films were then corona charged, and the electret charge stability was studied by means of isothermal and thermally stimulated surface potential decay. Both PTFE and LDPE films, after the surface treatment, displayed a considerable enhancement in the charge stability compared to the virgin samples. It is important to note that the enhancement of the charge stability was achieved in the positively charged PTFE films, a result important to practical applications. We attribute this effect of charge stabilization to the formation of new energetically deep traps on the modified surface. Decrease in molecular mobility, due to attachment of new chemical structures to the surface macro molecules, may also contribute to the overall growth of the charge stability.
  • TSZ Weißenburg
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Beitrag (Sammelband oder Tagungsband)
  • G. Kofod
  • H. Stoyanov
  • M. Kollosche
  • S. Risse
  • H. Ragusch
  • Dmitry Rychkov
  • M. Dansachmüller
  • D. McCarthy
Nano-scale Materials Science for Soft Dielectrics: Composites for Dielectric Elastomer Actuators
  • 2010

DOI: 10.1109/ICSD.2010.5568262

Electro-mechanical transducers based on soft elastomers can be improved by suitable manipulation of dielectric properties, mechanical stiffness and electric breakdown strength. The dielectric constant of an elastomer can be improved by mixing with other components with a higher dielectric constant, and both insulating or conducting filler materials may be employed. We present our results on insulating nanoparticulate TiO 2 with various chemical modifications, which may lead to devices with improved properties. Conducting nanoparticles such as carbon black may lead to percolation-related enhancement, though with strongly detrimental side effects. On the other hand, a “molecular composite” approach, in which the conducting nanoparticles are grafted chemically to the backbone, appears valuable.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
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Beitrag (Sammelband oder Tagungsband)
  • G. Kofod
  • D. McCarthy
  • H. Stoyanov
  • M. Kollosche
  • S. Risse
  • H. Ragusch
  • Dmitry Rychkov
  • M. Dansachmüller
  • R. Wache
Materials science on the nano-scale for improvements in actuation properties of dielectric elastomer actuators, pg. 76420J.
  • 2010

DOI: 10.1117/12.847281

We discuss various approaches to increasing the dielectric constant of elastomer materials, for use in dielectric elastomer actuators. High permittivity metal-oxide nano-particles can show elevated impact compared to larger size particles, but suffer from water uptake. Composites with conducting particles lead to extremely high permittivity caused by percolation, but they often suffer early breakdown. We present experiments on approaches combining metal-oxides and metal particles, which compensate for the drawbacks, and may lead to useful DEA materials in which all relevant properties are technologically useful. The key seems to be to avoid percolation and achieve a constant nearest-neighbor separation.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
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Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • M. Dansachmüller
  • H. Ragusch
  • A. Becker
  • G. Kofod
Force Relaxation in Charged Dielectric Elastomer Actuators
  • 2010

DOI: 10.1109/ICSD.2010.5568252

A new method for the investigation of dielectric elastomer actuators is developed, in which the relaxation of actuation force is observed under constant strain condition in an open-circuit regime. Independent isothermal surface potential decay measurements were employed to study the charge storage properties of the same elastomer materials. The following materials were used for dielectric elastomer actuators fabrication: VHB (adhesive films by 3M) and Poly-styrene-ethylene-butadiene-styrene (SEBS-Dryflex). It is found that actuation force relaxation kinetics is largely dependent on charge storage and transport properties of the actuator's dielectric elastomer material.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
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Beitrag (Sammelband oder Tagungsband)
  • McCarthy, D.N.
  • Dmitry Rychkov
  • H. Ragusch
  • S. Risse
  • M. Melzer
  • G. Kofod
Improved Dielectric Elastomer Actuator Materials Based on Ceramic-polymer Nanocomposites, pg. 448-451.

In: Actuator 10. 12th International Conference on New Actuators & 6th International Exhibition on Smart Actuators and Drive Systems ; 14-16 June 2010, Bremen, Germany (Actuator - International Conference and Exhibition on New Actuators and Drive Systems)

  • 2010
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • V. Golade
  • Rychkov, A. A.
  • Dmitry Rychkov
Electret Properties of Polymer Films and Fiber Materials Modified by Phosphorus Trichloride
  • 2010
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • G. Kofod
  • H. Stoyanov
  • S. Risse
  • M. Kollosche
  • McCarthy, D.N.
  • R. Kraehnert
  • H. Ragusch
  • Dmitry Rychkov
Improvement of Materials for Dielectric Elastomer Actuators Based on Conducting Particle Composites, pg. 888-891.

In: Actuator 10. 12th International Conference on New Actuators & 6th International Exhibition on Smart Actuators and Drive Systems ; 14-16 June 2010, Bremen, Germany (Actuator - International Conference and Exhibition on New Actuators and Drive Systems)

  • 2010
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • A. Kuznetsov
  • Dmitry Rychkov
Electret phenomenon in non-polar polymers with element-containing nanocomplexes on the surface, pg. 82-87.
  • 2009
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Zeitschriftenartikel
  • Rychkov, A. A.
  • Dmitry Rychkov
Mechanisms and models of electret phenomenon in non-polar polymers. (in Russian), vol. 95, pg. 47-62.

In: Izvestiya RGPU: Scientific Journal

  • 2009
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • V. Pak
  • Dmitry Rychkov
  • S. Trifonov
  • Rychkov, A. A.
Electret phenomenon in polymers with chemically modified surface, pg. 17-20.
  • 2008
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • P. Selyutin
  • Kuznetsov, A.
The stability of electret state in polyethylene films modified with phosphorus trichloride vapor, pg. 113-116.
  • 2008
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Zeitschriftenartikel
  • Dmitry Rychkov
  • Dergachev, V.F.
Homocharge transport in non-polar polymers with a gas-phase modified surface. (in Russian), vol. 48, pg. 75-82.

In: Izvestiya RGPU: Scientific Journal

  • 2008
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • Kuznetsov, A.
  • P. Selyutin
Electret phenomenon in low density polyethylene films with modified surface, pg. 74-77.
  • 2007
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Zeitschriftenartikel
  • Rychkov, A. A.
  • V. Pak
  • A. Kuznetsov
  • Dmitry Rychkov
  • R. Benberya
Phenomenon of electret charge stabilization in polytetraflouroethylene films with chemically modified surface. (in Russian), vol. 7, pg. 137-142.

In: Izvestiya RGPU: Scientific Journal

  • 2007
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Zeitschriftenartikel
  • Rychkov, A. A.
  • Dmitry Rychkov
  • S. Trifonov
Electret charge stability in film and fibrous polyethylene modified by phosphorus trichloride vapors. (in Russian), vol. 8, pg. 89-97.

In: Izvestiya RGPU: Scientific Journal

  • 2007
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Zeitschriftenartikel
  • Rychkov, A. A.
  • S. Trifonov
  • A. Kuznetsov
  • E. Sosnov
  • Dmitry Rychkov
  • A. Malygin
Influence of Chemical Modification of the Surface of Low-Density Polyethylene on Its Electret Properties, vol. 80, pg. 461-465.

In: Russian Journal of Applied Chemistry

  • 2007

DOI: 10.1134/S1070427207030214

The electret properties of low-density polyethylene with phosphorus-containing surface nanostructures were examined.
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Zeitschriftenartikel
  • Rychkov, A. A.
  • Dmitry Rychkov
Energy spectrum determination method for localized states on the surface of charged dielectrics. (in Russian), vol. 6, pg. 170-177.

In: Izvestiya RGPU: Scientific Journal

  • 2006
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Rychkov, A. A.
  • Dmitry Rychkov
  • S. Trifonov
  • Dergachev, V.F.
Electret charge stabilization in polymer films with element-containing nanostructures on the surface, pg. 52-53.
  • 2006
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • A. Kuznetsov
  • Rychkov, A. A.
  • A. Petrova
Energy spectrum of surface states in LDPE films modified with PCl3 vapours, pg. 26.
  • 2006
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • A. Kuznetsov
  • Dmitry Rychkov
  • R. Benberya
Electret phenomenon in polymers with modified surface, pg. 23-27.
  • 2006
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Zeitschriftenartikel
  • Rychkov, A. A.
  • Y. Gorokhovatsky
  • Dmitry Rychkov
  • A. Kuznetsov
Electret materials based on non-polar polymers with surface phosphorus-containing nanostructures. (in Russian), vol. 2, pg. 19-25.

In: Journal of Advanced Materials

  • 2006
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Rychkov, A. A.
  • Dmitry Rychkov
  • S. Trifonov
Electret phenomenon in film and fibrous LDPE modified by phosphorus trichloride vapors, pg. 7-13.
  • 2006
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • A. Kuznetsov
  • Rychkov, A. A.
Corona-charged electrets from phosphorus chloride vapor modified non-polar polymers, pg. 7-11.
  • 2005
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Zeitschriftenartikel
  • Rychkov, A. A.
  • Dmitry Rychkov
  • A. Kuznetsov
  • Y. Gerashenko
  • N. Kojevnikova
  • O. Kujelnaya
New electret materials based on polymers with modified surface and melt-blown polymers. (in Russian), vol. 5, pg. 204-219.

In: Izvestiya RGPU: Scientific Journal

  • 2005
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • A. Kuznetsov
  • Dmitry Rychkov
  • Rychkov, A. A.
Homocharge stability in low density polyethylene film electrets with surface phosphorus-containing nanostructures, pg. 112-116.
  • 2005
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
Electret phenomenon in tetrafluoroethylene-hexafluoropropylene copolymer with nanostructures built into the surface, pg. 68-71.
  • 2005
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Zeitschriftenartikel
  • Rychkov, A. A.
  • Y. Gorokhovatsky
  • Dmitry Rychkov
  • A. Kuznetsov
Electret phenomenon in non-polar fluoropolymers with phosphorus-containing nanostructures on the surface” Materials Technologies Instruments. (in Russian), vol. 10, pg. 74-78.

In: Materials Technologies Instruments

  • 2005
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Buch (Monographie)
  • Rychkov, A. A.
  • Dmitry Rychkov
  • S. Trifonov
Полимерные диэлектрики : учеб. пособие (Polymer dielectrics). A textbook for Engineering or Physics bachelor/master students
  • 2005
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Rychkov, A. A.
  • Y. Gorokhovatsky
  • Dmitry Rychkov
  • A. Kuznetsov
Electret phenomenon in non-polar fluoropolymers with phosphorus-containing nanostructures on the surface, pg. 45.
  • 2005
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Y. Gorokhovatsky
  • Dmitry Rychkov
  • Chepurnaya N.A.
  • Rychkov, A. A.
Electret phenomenon in polar partially crystalline polymers, pg. 283-285.
  • 2004
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Zeitschriftenartikel
  • Rychkov, A. A.
  • A. Malygin
  • S. Trifonov
  • Dmitry Rychkov
Influence of Chemical Modification of the Surface on the Electret Properties of Polytetrafluoroethylene, vol. 77, pg. 276-280.

In: Russian Journal of Applied Chemistry

  • 2004

DOI: 10.1023/B:RJAC.0000030366.96644.2c

Thermal stability of the electret state of polytetrafluoroethylene films with element oxide structures on the surface was studied. The frequency factor and the activation energies of the newly formed groups of deep centers that capture the electret charge were determined.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Rychkov, A. A.
  • Dmitry Rychkov
  • A. Kuznetsov
The stability of polymer electrets with surface nanostructures in severe climatic conditions, pg. 91-94.
  • 2004
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Rychkov, A. A.
  • Dmitry Rychkov
Microscopic parameters of electret charge traps in polymers with element-containing nanostructures on the surface, pg. 7-11.
  • 2004
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Zeitschriftenartikel
  • Rychkov, A. A.
  • Dmitry Rychkov
  • S. Trifonov
Electret state stability in polymers with modified surface. (in Russian), vol. 4, pg. 122-134.

In: Izvestiya RGPU: Scientific Journal

  • 2004
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Rychkov, A. A.
  • Dmitry Rychkov
  • S. Trifonov
Electret properties of polytetrafluoroethylene with element-containing nanostructures on the surface, pg. 308-311.
  • 2004
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • V. Boitzov
  • Dmitry Rychkov
  • Rychkov, A. A.
Test techniques for diagnostics of polar partially crystalline polymers, pg. 349-351.
  • 2003
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • S. Trifonov
  • A. Malygin
  • Dmitry Rychkov
The nature of electret charge traps in polymers with element-containing nanostructures on the surface, pg. 11-13.
  • 2003
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Rychkov, A. A.
  • Y. Gorokhovatsky
  • Dmitry Rychkov
Method for Determination of Polarization Decay in Polarized Polymer Films, pg. 805-807.
  • 2003
The novel voltage recovery technique is used for analysis of charge storage and transport in polymer electrets. We have shown that there is an opportunity to discriminate between real charge decay and polarization relaxation. This method enabled us to determine polarization relaxation kinetics in poled P(VDF-HFP) films. It has been shown that time interval of polarization relaxation comprises more than five decades at 290 K. Using appropriate analysis and experimental results we have determined real charge and polarization parameters.
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • Rychkov, A. A.
The effect of injected charges on dielectric properties of copolymer of vinylidenefluoride with hexafluoropropylene, pg. 41-43.
  • 2003
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • Rychkov, A. A.
Excess charge and polarization interaction in electret structures P(VDF-HFP)-Al, pg. 74-76.
  • 2003
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Rychkov, A. A.
  • Dmitry Rychkov
Isothermal surface potential decay in polymer-metal structures, pg. 12-15.
  • 2003
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Rychkov, A. A.
  • Dmitry Rychkov
  • Dergachev, V.F.
Fluoropolymers surface modification in technologies of thermally stable electret production, pg. 44-48.
  • 2003
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Rychkov, A. A.
  • Dmitry Rychkov
Electret state formation and relaxation in polymers, pg. 7-11.
  • 2003
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • Y. Gorokhovatsky
Polarization relaxation kinetics determination by thermally stimulated surface voltage recovery method, pg. 213-215.
  • 2002
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
Modeling of isothermal potential decay in polar polymer electrets, pg. 67-71.
  • 2002
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Y. Gorokhovatsky
  • V. Boitzov
  • Dmitry Rychkov
Thermal stability of polarization structures in corona-charged P(VDF-HFP) copolymers films, pg. 134-137.
  • 2002

DOI: 10.1109/ISE.2002.1042962

The trapping of charge carriers in localized states on the surface of /spl beta/-crystallites in P(VDF-HFP) films has been studied by means of a novel voltage recovery technique. It has been found that a phase transition from /spl alpha/-non polar to the /spl delta/-polar configuration takes place under the process of charge injection. Using experimental measurements and appropriate analysis, we determine the energy distribution of the traps located near the /spl beta/-crystallites surfaces, and estimate the spatial dimensions of the molecular dipoles to be about 11-12 nm. The industrial application method was suggested in order to improve the thermal stability of charge and polarization in corona-charged copolymer films.
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • V. Boitzov
  • Dmitry Rychkov
Technological features of industrial electrets and electret microphones production, pg. 309-311.
  • 2002
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
The effect of corona discharge treatment on thermal stability of copolymer of vinylidenefluoride with hexafluoropropylene film electrets, pg. 212-214.
  • 2002
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Y. Gorokhovatsky
  • Dmitry Rychkov
  • Semikhin Y.A.
Determination of frequency factor and activation energy distributions in copolymer of vinylidenefluoride with hexafluoropropylene, pg. 64-66.
  • 2002
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
Modeling of thermally stimulated surface potential relaxation in film structures containing polar dielectric, pg. 24-29.
  • 2002
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • S. Trifonov
  • Dmitry Rychkov
  • Dergachev, V.F.
Relaxation properties of polymers with surface modified with molecular layer formation technique, pg. 62-64.
  • 2002
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Zeitschriftenartikel
  • V. Boitzov
  • Dmitry Rychkov
Polymeric electrets in innovative technologies. (in Russian), vol. 2, pg. 118-133.

In: Izvestiya RGPU: Scientific Journal

  • 2002
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
  • V. Boitzov
Voltage recovery kinetics in electret structures (P(VDF-HFP)) after short-circuiting, pg. 83-85.
  • 2001
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG
Zeitschriftenartikel
  • V. Boitzov
  • Dmitry Rychkov
Novel polymeric materials for electret and piezoelectric transducers. (in Russian), vol. 12, pg. 46-48.

In: Izvestiya RGPU: Scientific Journal

  • 2001
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • V. Boitzov
  • Dmitry Rychkov
Electret phenomenon in copolymer of vinylidenefluoride with hexafluoropropylene, pg. 86-88.
  • 2001
  • TSZ Weißenburg
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • NACHHALTIG
Beitrag (Sammelband oder Tagungsband)
  • Dmitry Rychkov
Measuring complex for investigation of electret state in polar polymers, pg. 89-90.
  • 2000
  • Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen
  • TSZ Weißenburg
  • NACHHALTIG