Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341589
Takeo Purukawa
The piezoelectric and pyroelectric constants of various ferroelectric polymers have been determined as a function of remanent polarization created as a result of poling. The results are compared with predicted activities arising from macroscopic dimensional changes and rigid dipoles. It is shown that the dimensional effect is dominant in the piezoelectric activity of undrawn polymers. In drawn polymers having relatively low Curie point, however, stress-induced changes in dipole orientation through the electro-strictive coupling play an important role. Pyroelectric activity primarily arises from temperature-induced disordering of dipoles.
{"title":"Piezoelectricity and pyroelectricity in ferroelectric polymers","authors":"Takeo Purukawa","doi":"10.1109/ISE.1985.7341589","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341589","url":null,"abstract":"The piezoelectric and pyroelectric constants of various ferroelectric polymers have been determined as a function of remanent polarization created as a result of poling. The results are compared with predicted activities arising from macroscopic dimensional changes and rigid dipoles. It is shown that the dimensional effect is dominant in the piezoelectric activity of undrawn polymers. In drawn polymers having relatively low Curie point, however, stress-induced changes in dipole orientation through the electro-strictive coupling play an important role. Pyroelectric activity primarily arises from temperature-induced disordering of dipoles.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"74 1","pages":"883-888"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74964480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341521
T. Takada, T. Maeno, H. Kushibe
The determination of the amount and distribution profile of charges in insulators has been studied by various methods, some of them utilizing thermal, mechanical and electrical stimulations. A new method incorporating pulse electrical stimulations and pulse acoustic detection is reported here, along with the preliminary results of the measurement of the amount and distribution profile of charges in electron-beam irradiated polymethyl methacrylate (PMMA) samples. The amount and the distribution of charges are obtained by the size and timing of acoustic signals produced in response to a high voltage impulse applied to the sample. Thus, determination of the profile of the spatial charge distribution in a sample became possible. A 5 mm thick PMMA plate irradiated with 1 MeV electrons at 0.5 −3.0 Mrads was found to trap charges of approximately −0.3 μC/cm2 at a mean depth of about 2 mm.
{"title":"An electric stress pulse technique for the measurement of charges in a plastic plate irradiated by an electron beam","authors":"T. Takada, T. Maeno, H. Kushibe","doi":"10.1109/ISE.1985.7341521","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341521","url":null,"abstract":"The determination of the amount and distribution profile of charges in insulators has been studied by various methods, some of them utilizing thermal, mechanical and electrical stimulations. A new method incorporating pulse electrical stimulations and pulse acoustic detection is reported here, along with the preliminary results of the measurement of the amount and distribution profile of charges in electron-beam irradiated polymethyl methacrylate (PMMA) samples. The amount and the distribution of charges are obtained by the size and timing of acoustic signals produced in response to a high voltage impulse applied to the sample. Thus, determination of the profile of the spatial charge distribution in a sample became possible. A 5 mm thick PMMA plate irradiated with 1 MeV electrons at 0.5 −3.0 Mrads was found to trap charges of approximately −0.3 μC/cm2 at a mean depth of about 2 mm.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"1 1","pages":"450-455"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90045306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341585
D. Geiss, R. Danz, A. Janke, W. Kunstler
Uniaxially stretched poly (vinylidene fluoride) (PVDF) films containing β-phase only or both α and β-phases as well as 12/um biaxially oriented commercial PVDF-films were investigated by means of modified x-ray and infrared techniques. The structural changes were examined in response to the applied poling field (≤ 450 MV/m) and the poling temperature at various levels. The changes in the orientation state determined by pole figure measurements, the various crystal phase transitions, the conformational conversion TGTS in TT, and the increase of ciystallinity in the β-phase were discussed in comparison with the piezoelectric strain and stress coefficients d31 and e31.
{"title":"Field induced structure transition in poly (vinylidene fluoride)","authors":"D. Geiss, R. Danz, A. Janke, W. Kunstler","doi":"10.1109/ISE.1985.7341585","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341585","url":null,"abstract":"Uniaxially stretched poly (vinylidene fluoride) (PVDF) films containing β-phase only or both α and β-phases as well as 12/um biaxially oriented commercial PVDF-films were investigated by means of modified x-ray and infrared techniques. The structural changes were examined in response to the applied poling field (≤ 450 MV/m) and the poling temperature at various levels. The changes in the orientation state determined by pole figure measurements, the various crystal phase transitions, the conformational conversion TGTS in TT, and the increase of ciystallinity in the β-phase were discussed in comparison with the piezoelectric strain and stress coefficients d31 and e31.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"15 1","pages":"857-864"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73270837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341500
H. von Berlepsch, L. Brehmer, D. Geiss
Based on measurements of the isothermal surface potential kinetics the charge carrier transport in HDPE is investigated. A simple mathematical model for discribing the surface potential kinetics is presented involving hopping transport of injected charge carriers being modulated by shallow and deep traps at the surface and in the bulk. The model parameters, as charge carrier mobility, hopping distance, trap concentration, trap depth and attempt-to-escape frequency were determined by curve fitting. The resulting dependence of mobility and lifetime on the field strength is discussed.
{"title":"Trap-controlled hopping in HDPE","authors":"H. von Berlepsch, L. Brehmer, D. Geiss","doi":"10.1109/ISE.1985.7341500","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341500","url":null,"abstract":"Based on measurements of the isothermal surface potential kinetics the charge carrier transport in HDPE is investigated. A simple mathematical model for discribing the surface potential kinetics is presented involving hopping transport of injected charge carriers being modulated by shallow and deep traps at the surface and in the bulk. The model parameters, as charge carrier mobility, hopping distance, trap concentration, trap depth and attempt-to-escape frequency were determined by curve fitting. The resulting dependence of mobility and lifetime on the field strength is discussed.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"86 1","pages":"316-321"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74199732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341466
J. Ulański, J. K. Jeszka, Ireneusz Geowacki, M. Kryszewski
The surface component of absorption/resorption currents i.e. the component related to the electrode edge is investigated-Different electrode preparation techniques are used to obtain qualitative modification of the electrode edge geometry, the most unusual being reticulate CT complex electrodes. It was found that the surface component of absorption/resorption currents in polycarbonate is very sensitive to the electrode preparation. It increases by about an order of magnitude for reticulate CT complex electrode or "tapered" metal electrode as compared with conventional metal electrodes or pressed conductive films. The phenomenon is interpreted in terms of high field injection in the viscinity of sharp electrode edges.
{"title":"Surface component of absorption/resorption currents in polycarbonate for different electrodes","authors":"J. Ulański, J. K. Jeszka, Ireneusz Geowacki, M. Kryszewski","doi":"10.1109/ISE.1985.7341466","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341466","url":null,"abstract":"The surface component of absorption/resorption currents i.e. the component related to the electrode edge is investigated-Different electrode preparation techniques are used to obtain qualitative modification of the electrode edge geometry, the most unusual being reticulate CT complex electrodes. It was found that the surface component of absorption/resorption currents in polycarbonate is very sensitive to the electrode preparation. It increases by about an order of magnitude for reticulate CT complex electrode or \"tapered\" metal electrode as compared with conventional metal electrodes or pressed conductive films. The phenomenon is interpreted in terms of high field injection in the viscinity of sharp electrode edges.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"15 1","pages":"112-116"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74978393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341512
A. Toureille, J. Reboul
Special-shaped PE samples as thin as 200 μm in their middle part and becoming thicker toward the edges have been machined from 3 cm thick slabs. Such samples have been charged under high DC voltage in the range of 20 kV, without any corona leakage. TSD studies have been carried out using both the common method and a new differential technique. An attempt of interpretation involving the assumption of a floating space charge according to Leal Ferreira's model agrees with our experimental results.
{"title":"High-voltage charging technique and TSD studies of polyethylene thermo-electrets\"","authors":"A. Toureille, J. Reboul","doi":"10.1109/ISE.1985.7341512","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341512","url":null,"abstract":"Special-shaped PE samples as thin as 200 μm in their middle part and becoming thicker toward the edges have been machined from 3 cm thick slabs. Such samples have been charged under high DC voltage in the range of 20 kV, without any corona leakage. TSD studies have been carried out using both the common method and a new differential technique. An attempt of interpretation involving the assumption of a floating space charge according to Leal Ferreira's model agrees with our experimental results.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"7 1","pages":"386-392"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81799838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341506
M. Lal, R. Parshad
A new mechanism of charge decay of electrets is proposed. In this mechanism the observed charge decay is only apparent and due to screening (not cancellation) of the electret charge at the atomic or microscopic level by electrical charges drawn from ions in the atmosphere or by electrical loading. The water film on the electret and the finite conductivity of the material constitute forms of electrical loading. The Cancellation of charge is avoided by the free charge being isolated in traps or the charge being due to exposed ends of aligned dipoles or both. It has been possible to evolve a process, essentially based on contacting each of the electret surfaces, one at a time, to a metal plate, to remove the screening charge and thus activate the (apparently) decayed electret, thus making life of the treated electrets almost infinite.
{"title":"A suggested new mechanism of charge decay of electrets and its application to their charge recovery","authors":"M. Lal, R. Parshad","doi":"10.1109/ISE.1985.7341506","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341506","url":null,"abstract":"A new mechanism of charge decay of electrets is proposed. In this mechanism the observed charge decay is only apparent and due to screening (not cancellation) of the electret charge at the atomic or microscopic level by electrical charges drawn from ions in the atmosphere or by electrical loading. The water film on the electret and the finite conductivity of the material constitute forms of electrical loading. The Cancellation of charge is avoided by the free charge being isolated in traps or the charge being due to exposed ends of aligned dipoles or both. It has been possible to evolve a process, essentially based on contacting each of the electret surfaces, one at a time, to a metal plate, to remove the screening charge and thus activate the (apparently) decayed electret, thus making life of the treated electrets almost infinite.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"39 1","pages":"352-357"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74336699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341596
F. Bauer, Klaus Harnischmacher, Jacques Riha
Polyvinylidene fluoride PVF2 and VF2/C2F3H copolytners present strong piezoelectric activities under specific conditions of crystallization and polarization. The piezoelectric activity of PVF2 depends on the polarization process as it is presented in the hysteresis loops P(E) (P polarization, E electrical field). The remanent polarization attains 10 p.C/cm2 for biaxially stretched PVF2 films. Results obtained on VF2/C2F3H copolymers are also reported. Properties of these well clean and uniform poled ferroelectric materials, under static, dynamic pressure and shock wave action are presented and discussed. These organic piezoelectric materials are strong candidates for shock gauges and new transducers.
{"title":"Ferroelectric polarization of PVF2 and VF2/C2F3H copolymers: Piezoelectric properties under dynamic pressure and shock loading","authors":"F. Bauer, Klaus Harnischmacher, Jacques Riha","doi":"10.1109/ISE.1985.7341596","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341596","url":null,"abstract":"Polyvinylidene fluoride PVF<inf>2</inf> and VF<inf>2</inf>/C<inf>2</inf>F<inf>3</inf>H copolytners present strong piezoelectric activities under specific conditions of crystallization and polarization. The piezoelectric activity of PVF<inf>2</inf> depends on the polarization process as it is presented in the hysteresis loops P(E) (P polarization, E electrical field). The remanent polarization attains 10 p.C/cm<sup>2</sup> for biaxially stretched PVF<inf>2</inf> films. Results obtained on VF<inf>2</inf>/C<inf>2</inf>F<inf>3</inf>H copolymers are also reported. Properties of these well clean and uniform poled ferroelectric materials, under static, dynamic pressure and shock wave action are presented and discussed. These organic piezoelectric materials are strong candidates for shock gauges and new transducers.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"10 1","pages":"924-929"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90928953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341551
Ž. Jelčić, F. Ranogajec
The thermally stimulated depolarization(TSD) currents of unsaturated polyester(UP) resin thermoelectrets have been measured in the low temperature range. The study of the decrease of the current intensity as a function of the absorbed dose reveals important differences between the peaks of the spectrum; the low temperature peaks can be attributed to dipolar volume polarization, and £he high temperature peaks to an ionic space charge polarization. The shift of the peaks may be indicative of plasticization of the polyester by styrene, and of restriction upon motions of the chain imposed by the crosslinks. The l-peak could be manifestation of the liquid-liquid(Tll) transition, from the Tll/Tg ratio, and here it corresponds to the thermally activated disintegration of phase separated structures, which were well documented in the inherently heterogeneous UP resins.
{"title":"Radiation crosslinking effect on thermally stimulated current spectra of unsaturated polyester resins","authors":"Ž. Jelčić, F. Ranogajec","doi":"10.1109/ISE.1985.7341551","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341551","url":null,"abstract":"The thermally stimulated depolarization(TSD) currents of unsaturated polyester(UP) resin thermoelectrets have been measured in the low temperature range. The study of the decrease of the current intensity as a function of the absorbed dose reveals important differences between the peaks of the spectrum; the low temperature peaks can be attributed to dipolar volume polarization, and £he high temperature peaks to an ionic space charge polarization. The shift of the peaks may be indicative of plasticization of the polyester by styrene, and of restriction upon motions of the chain imposed by the crosslinks. The l-peak could be manifestation of the liquid-liquid(Tll) transition, from the Tll/Tg ratio, and here it corresponds to the thermally activated disintegration of phase separated structures, which were well documented in the inherently heterogeneous UP resins.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"42 1","pages":"648-652"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84761350","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1985-09-01DOI: 10.1109/ISE.1985.7341581
M. G. Bridelli, R. Capelletti, G. Ruani, A. Vecli
The role of water in a bioelectret such as lysozyme at different hydration levels is studied by coupling TSDC and i.r. absorption measurements. In addition to the 312 K-band reported by Mascarenhas, our TSDC spectra exhibit new, weaker but anyway relevant bands related to water in different coordinations. At fixed starting hydration levels, the time evolution of water contents was studied by isothermal sample aging in dynamic vacuum: 1) the whole TSDC spectrum was reduced, the decrease being more relevant on the high temperature side and 2) the water related i.r. bands decreased as well.
{"title":"Water induced bioelectret state in lysozyme","authors":"M. G. Bridelli, R. Capelletti, G. Ruani, A. Vecli","doi":"10.1109/ISE.1985.7341581","DOIUrl":"https://doi.org/10.1109/ISE.1985.7341581","url":null,"abstract":"The role of water in a bioelectret such as lysozyme at different hydration levels is studied by coupling TSDC and i.r. absorption measurements. In addition to the 312 K-band reported by Mascarenhas, our TSDC spectra exhibit new, weaker but anyway relevant bands related to water in different coordinations. At fixed starting hydration levels, the time evolution of water contents was studied by isothermal sample aging in dynamic vacuum: 1) the whole TSDC spectrum was reduced, the decrease being more relevant on the high temperature side and 2) the water related i.r. bands decreased as well.","PeriodicalId":6451,"journal":{"name":"1985 5th International Symposium on Electrets (ISE 5)","volume":"8 1","pages":"831-835"},"PeriodicalIF":0.0,"publicationDate":"1985-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81511899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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