Pub Date : 2002-12-10DOI: 10.1109/ISE.2002.1042986
J. Ohga, K. Matsushita, T. Takei, N. Moriyama
A bimorph sheet of PVDF (polyvinylidenfluoride) film is applied to a flat rectangular loudspeaker as a folded zigzag-tuck shape diaphragm whose size is, for example, 240 mm/spl times/114 mm. This loudspeaker is characterized by moderate size with a wide frequency range, light weight and no magnetic flux radiation. This paper shows measuring results of acoustical and electrical characteristics by using a few samples, and the output level is examined by theoretical calculations.
{"title":"Rectangular loudspeaker by tuck shape PVDF bimorph","authors":"J. Ohga, K. Matsushita, T. Takei, N. Moriyama","doi":"10.1109/ISE.2002.1042986","DOIUrl":"https://doi.org/10.1109/ISE.2002.1042986","url":null,"abstract":"A bimorph sheet of PVDF (polyvinylidenfluoride) film is applied to a flat rectangular loudspeaker as a folded zigzag-tuck shape diaphragm whose size is, for example, 240 mm/spl times/114 mm. This loudspeaker is characterized by moderate size with a wide frequency range, light weight and no magnetic flux radiation. This paper shows measuring results of acoustical and electrical characteristics by using a few samples, and the output level is examined by theoretical calculations.","PeriodicalId":331115,"journal":{"name":"Proceedings. 11th International Symposium on Electrets","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116681393","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 : 2002-12-10DOI: 10.1109/ISE.2002.1042993
N. Alves, C. X. Cardoso, A. Job, J. Giacometti
This work reports on the effects from thermal treatment in poly(vinylidene fluoride), PVDF, obtained with differential scanning calorimetry (DSC) and dynamic thermal analysis (DMA) measurements. It is shown that in successive DMA measurements performed with one sample the a relaxation peak almost disappears while the /spl gamma/ ' peak appears. The /spl alpha/ relaxation peak, at /spl sim/100/spl deg/C in DMA measurements, is attributed to the preferential orientation of chains in the amorphous phase while the /spl gamma/ ' relaxation peak, at /spl sim/50/spl deg/C, is related to the thermal treatment to which the sample was submitted.
{"title":"Effects of thermal treatment on phase transitions and on the mechanical relaxation in poly(vinylidene fluoride)","authors":"N. Alves, C. X. Cardoso, A. Job, J. Giacometti","doi":"10.1109/ISE.2002.1042993","DOIUrl":"https://doi.org/10.1109/ISE.2002.1042993","url":null,"abstract":"This work reports on the effects from thermal treatment in poly(vinylidene fluoride), PVDF, obtained with differential scanning calorimetry (DSC) and dynamic thermal analysis (DMA) measurements. It is shown that in successive DMA measurements performed with one sample the a relaxation peak almost disappears while the /spl gamma/ ' peak appears. The /spl alpha/ relaxation peak, at /spl sim/100/spl deg/C in DMA measurements, is attributed to the preferential orientation of chains in the amorphous phase while the /spl gamma/ ' relaxation peak, at /spl sim/50/spl deg/C, is related to the thermal treatment to which the sample was submitted.","PeriodicalId":331115,"journal":{"name":"Proceedings. 11th International Symposium on Electrets","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124979162","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 : 2002-12-10DOI: 10.1109/ISE.2002.1042963
Y. Gorokhovatsky, D. Temnov, O.V. Kuvshinova, V. Goldade, W. Stark, S. Krueger, K. Brademann-Jock
Low density polyethylene (LDPE) fiber materials, produced by melt-blown technology, were investigated, which are important for the production of electret filters. The paper presents the results of a comparative investigation of the thermally stimulated luminescence irradiated by electron gun in the films and fibers based on LDPE. There are three relaxation processes, which take place in the temperature interval 80-300 K: /spl gamma/-process in the temperature range 110 K, which is connected with the end and side groups of macromolecules of polymer chain, /spl beta/-process in the temperature range 150 K, which is connected with the emptying of electronic capture centers due to dipole-group mobility, and /spl alpha/-process in the temperature range 230 K which is connected with the defrosting of segmental mobility due to the phase transition from glass to high elastic state. It is important to point out that all processes observed in fibers and films can be explained at the molecular level of the given polymer structure. At the same time the comparison with the polymer film of the same material some processes in fibers meet some difficulties, which finally leads to an increase of electret stability in fiber materials.
{"title":"Thermally stimulated luminescence in LDPE fibers","authors":"Y. Gorokhovatsky, D. Temnov, O.V. Kuvshinova, V. Goldade, W. Stark, S. Krueger, K. Brademann-Jock","doi":"10.1109/ISE.2002.1042963","DOIUrl":"https://doi.org/10.1109/ISE.2002.1042963","url":null,"abstract":"Low density polyethylene (LDPE) fiber materials, produced by melt-blown technology, were investigated, which are important for the production of electret filters. The paper presents the results of a comparative investigation of the thermally stimulated luminescence irradiated by electron gun in the films and fibers based on LDPE. There are three relaxation processes, which take place in the temperature interval 80-300 K: /spl gamma/-process in the temperature range 110 K, which is connected with the end and side groups of macromolecules of polymer chain, /spl beta/-process in the temperature range 150 K, which is connected with the emptying of electronic capture centers due to dipole-group mobility, and /spl alpha/-process in the temperature range 230 K which is connected with the defrosting of segmental mobility due to the phase transition from glass to high elastic state. It is important to point out that all processes observed in fibers and films can be explained at the molecular level of the given polymer structure. At the same time the comparison with the polymer film of the same material some processes in fibers meet some difficulties, which finally leads to an increase of electret stability in fiber materials.","PeriodicalId":331115,"journal":{"name":"Proceedings. 11th International Symposium on Electrets","volume":"107 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115046368","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 : 2002-12-10DOI: 10.1109/ISE.2002.1043012
P. Vartzeli-Nikaki, S. Kripotou, A. Konsta
The hydration mechanism of various polysaccharides of plant origin has been investigated by means of several physicochemical and dielectric techniques. In this work, we present, more particularly, results obtained with potato starch samples, using (a) equilibrium water sorption isotherms and (b) Thermally Stimulated Depolarization Currents (TSDC) techniques in the temperature range 77-300 K. The water content of our samples, defined as the ratio of weight of sorbed water to the weight of dry sample, varied between 2.4% and 41%. The results of equilibrium water sorption measurements were analyzed by fitting experimental data to the Guggenheim-Anderson-De Boer (GAB) equation. Two main relaxation regions are observed in TSDC spectra; the dependence of their characteristics on the water content is investigated and their origin is interpreted on the basis of results obtained in the first part of this work.
{"title":"Dielectric investigation of the hydration mechanism in potato starch","authors":"P. Vartzeli-Nikaki, S. Kripotou, A. Konsta","doi":"10.1109/ISE.2002.1043012","DOIUrl":"https://doi.org/10.1109/ISE.2002.1043012","url":null,"abstract":"The hydration mechanism of various polysaccharides of plant origin has been investigated by means of several physicochemical and dielectric techniques. In this work, we present, more particularly, results obtained with potato starch samples, using (a) equilibrium water sorption isotherms and (b) Thermally Stimulated Depolarization Currents (TSDC) techniques in the temperature range 77-300 K. The water content of our samples, defined as the ratio of weight of sorbed water to the weight of dry sample, varied between 2.4% and 41%. The results of equilibrium water sorption measurements were analyzed by fitting experimental data to the Guggenheim-Anderson-De Boer (GAB) equation. Two main relaxation regions are observed in TSDC spectra; the dependence of their characteristics on the water content is investigated and their origin is interpreted on the basis of results obtained in the first part of this work.","PeriodicalId":331115,"journal":{"name":"Proceedings. 11th International Symposium on Electrets","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122047547","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 : 2002-12-10DOI: 10.1109/ISE.2002.1042990
I. Muzikante, E. Fonavs, R. Dobulāns, A. Tokmakov, B. Stiller, L. Brehmer, O. Neilands
In this work betaine-type molecules were investigated. As a result of the asymmetry of charge distribution, molecules in the ground state have a considerable permanent dipole moment. The thermally stimulated surface potential dependences on poling temperature are investigated. The influence of /spl alpha/- and /spl beta/-relaxations of PMMA on the surface potential of the film are shown. The thermal dependence of surface potential is discussed. The transition temperature, where no changes of the surface potential appeared, is related to glass transition temperature of the host-guest system.
{"title":"The thermally stimulated surface potential of betaine type host-guest polymer films","authors":"I. Muzikante, E. Fonavs, R. Dobulāns, A. Tokmakov, B. Stiller, L. Brehmer, O. Neilands","doi":"10.1109/ISE.2002.1042990","DOIUrl":"https://doi.org/10.1109/ISE.2002.1042990","url":null,"abstract":"In this work betaine-type molecules were investigated. As a result of the asymmetry of charge distribution, molecules in the ground state have a considerable permanent dipole moment. The thermally stimulated surface potential dependences on poling temperature are investigated. The influence of /spl alpha/- and /spl beta/-relaxations of PMMA on the surface potential of the film are shown. The thermal dependence of surface potential is discussed. The transition temperature, where no changes of the surface potential appeared, is related to glass transition temperature of the host-guest system.","PeriodicalId":331115,"journal":{"name":"Proceedings. 11th International Symposium on Electrets","volume":"175 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124297719","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 : 2002-12-10DOI: 10.1109/ISE.2002.1042952
X. Huang, X.S. Xie, Z. Wu
When a super-thin film electret is evaporated with metal electrodes on two sides, the electrons in electrodes have the possibility of crossing potential area in film. Suppose the electrons obey Fermi-distribution, it is found that the tunnel current across the film depends on both exerted voltage between the film and the thickness of the film. The temperature and work function of electrode-metal also have significant effects on the current. If exerted electrical field is very large, the result of calculation shows that the current can be proportional to exerted voltage in certain conditions.
{"title":"Tunnel current across super-thin film electrets","authors":"X. Huang, X.S. Xie, Z. Wu","doi":"10.1109/ISE.2002.1042952","DOIUrl":"https://doi.org/10.1109/ISE.2002.1042952","url":null,"abstract":"When a super-thin film electret is evaporated with metal electrodes on two sides, the electrons in electrodes have the possibility of crossing potential area in film. Suppose the electrons obey Fermi-distribution, it is found that the tunnel current across the film depends on both exerted voltage between the film and the thickness of the film. The temperature and work function of electrode-metal also have significant effects on the current. If exerted electrical field is very large, the result of calculation shows that the current can be proportional to exerted voltage in certain conditions.","PeriodicalId":331115,"journal":{"name":"Proceedings. 11th International Symposium on Electrets","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127686014","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 : 2002-12-10DOI: 10.1109/ISE.2002.1042987
É. Dantras, E. Dudognon, A. Bernés, C. Lacabanne
In order to improve, in polymeric materials, the understanding of the nature of molecular mobility and the hierarchy of dipolar movements, we analyse the dipolar polarisation. This study is realised on model polymers with two types of architectures, linear and dendritic, to emphasise the part played by the chain structure. For this dielectric study, we use the dynamic dielectric spectroscopy, that allows us to sweep a wide frequency range (10/sup -2/-10/sup 6/ Hz), and the thermo-stimulated currents technique, that allows us to determine experimentally the fine structure of complex relaxations. We show that a type of polarisation (radiofrequency, low frequency and very low frequency polarisation) can be directly related to a kind of molecular mobility: localised and noncooperative motions, then more delocalised and cooperative motions and, finally, motions delocalised along the entire chain.
{"title":"Study of polymers with various chemical structures and chain architectures by thermo-stimulated currents and broadband dielectric spectroscopy","authors":"É. Dantras, E. Dudognon, A. Bernés, C. Lacabanne","doi":"10.1109/ISE.2002.1042987","DOIUrl":"https://doi.org/10.1109/ISE.2002.1042987","url":null,"abstract":"In order to improve, in polymeric materials, the understanding of the nature of molecular mobility and the hierarchy of dipolar movements, we analyse the dipolar polarisation. This study is realised on model polymers with two types of architectures, linear and dendritic, to emphasise the part played by the chain structure. For this dielectric study, we use the dynamic dielectric spectroscopy, that allows us to sweep a wide frequency range (10/sup -2/-10/sup 6/ Hz), and the thermo-stimulated currents technique, that allows us to determine experimentally the fine structure of complex relaxations. We show that a type of polarisation (radiofrequency, low frequency and very low frequency polarisation) can be directly related to a kind of molecular mobility: localised and noncooperative motions, then more delocalised and cooperative motions and, finally, motions delocalised along the entire chain.","PeriodicalId":331115,"journal":{"name":"Proceedings. 11th International Symposium on Electrets","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125749329","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 : 2002-12-10DOI: 10.1109/ISE.2002.1043008
X. Qiu, Z. Xia, F. Wang, Y. Wu, Y. Zhang
By positively and negatively corona charging at room and elevated temperatures, measurements of surface potential decay, thermally stimulated discharge (TSD) current spectra in combination with the heat pulse technology, the electret character of the copolymer P(VDF/CTFE) film, polymerized from vinylidenefluoride (VDF) and chlorotrifluorethylene (CTFE), has been studied. The space charge storage capability of P(VDF/CTFE) is significantly greater than that of PVDF. P(VDF/CTFE) is a polar material, i.e. it contains both dipoles and space charges in the material. Moreover the space charge storage ability of positively and negatively corona charged samples has been compared, and the geometric distribution of traps has been studied. Finally, the shift of mean charge depth with charging temperature has been investigated.
{"title":"The electret behavior of poly(vinylidenefluoride/chlorotrifluorethylene) film","authors":"X. Qiu, Z. Xia, F. Wang, Y. Wu, Y. Zhang","doi":"10.1109/ISE.2002.1043008","DOIUrl":"https://doi.org/10.1109/ISE.2002.1043008","url":null,"abstract":"By positively and negatively corona charging at room and elevated temperatures, measurements of surface potential decay, thermally stimulated discharge (TSD) current spectra in combination with the heat pulse technology, the electret character of the copolymer P(VDF/CTFE) film, polymerized from vinylidenefluoride (VDF) and chlorotrifluorethylene (CTFE), has been studied. The space charge storage capability of P(VDF/CTFE) is significantly greater than that of PVDF. P(VDF/CTFE) is a polar material, i.e. it contains both dipoles and space charges in the material. Moreover the space charge storage ability of positively and negatively corona charged samples has been compared, and the geometric distribution of traps has been studied. Finally, the shift of mean charge depth with charging temperature has been investigated.","PeriodicalId":331115,"journal":{"name":"Proceedings. 11th International Symposium on Electrets","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131643503","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 : 2002-12-10DOI: 10.1109/ISE.2002.1043000
A. Ilinskii, V. Klimov, A. Sidorov, I. Timofeeva, S. D. Khanin, E. Shadrin
The optical and electrical properties of thin film Fabri-Perrout interferometers on the base of VO/sub 2/ and Ag/sub 2/S are studied. The possibility of using of interferometers as optical limiters, femtosecond Q-switchers and materials for holograms recording is shown. The comparative analysis of the physical characteristics of films of the polycrystalline and amorphous vanadium dioxide. The morphology of films is studied on AFM-microscope. The phenomenological mechanisms of a hysteresis loop formation by metal insulator phase transition and superionic conductor - insulator phase transition are discussed.
{"title":"Application of non-linear properties of transition metal compounds as optical limiters","authors":"A. Ilinskii, V. Klimov, A. Sidorov, I. Timofeeva, S. D. Khanin, E. Shadrin","doi":"10.1109/ISE.2002.1043000","DOIUrl":"https://doi.org/10.1109/ISE.2002.1043000","url":null,"abstract":"The optical and electrical properties of thin film Fabri-Perrout interferometers on the base of VO/sub 2/ and Ag/sub 2/S are studied. The possibility of using of interferometers as optical limiters, femtosecond Q-switchers and materials for holograms recording is shown. The comparative analysis of the physical characteristics of films of the polycrystalline and amorphous vanadium dioxide. The morphology of films is studied on AFM-microscope. The phenomenological mechanisms of a hysteresis loop formation by metal insulator phase transition and superionic conductor - insulator phase transition are discussed.","PeriodicalId":331115,"journal":{"name":"Proceedings. 11th International Symposium on Electrets","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133641523","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 : 2002-12-10DOI: 10.1109/ISE.2002.1043023
M. Wegener, R. Gerhard-Multhaupt
Many sensor and actuator applications were proposed for piezoelectric polymers. Coaxial cables with piezoelectric polymer layers are highly suitable and attractive for a range of these applications. Because of the mechanical stiffness required of such cables, the most common materials for use in sensor cables are nonporous piezoelectric polymers such as polyvinylidene fluoride (PVDF) or its copolymer with trifluoroethylene (P(VDF-TrFE)). Here, we first describe the operating principle and the geometry of piezoelectric polymer cables. As an active piezoelectric layer, P(VDF-TrFE) (76/24) was employed. After electrical poling with one or more point-to-cable corona discharges, we investigated the polarization in the P(VDF-TrFE) layer. Poling parameters such as electric field, poling time and distance between cable and corona needle were varied. The resulting polarization was characterized with measurements of polarization profiles across the layer thickness. The poling process developed here leads to good piezoelectric properties of the cable layer. Finally, discuss the sensor properties of the cable.
{"title":"Poling of piezoelectric polymer cables and assessment of their sensor properties","authors":"M. Wegener, R. Gerhard-Multhaupt","doi":"10.1109/ISE.2002.1043023","DOIUrl":"https://doi.org/10.1109/ISE.2002.1043023","url":null,"abstract":"Many sensor and actuator applications were proposed for piezoelectric polymers. Coaxial cables with piezoelectric polymer layers are highly suitable and attractive for a range of these applications. Because of the mechanical stiffness required of such cables, the most common materials for use in sensor cables are nonporous piezoelectric polymers such as polyvinylidene fluoride (PVDF) or its copolymer with trifluoroethylene (P(VDF-TrFE)). Here, we first describe the operating principle and the geometry of piezoelectric polymer cables. As an active piezoelectric layer, P(VDF-TrFE) (76/24) was employed. After electrical poling with one or more point-to-cable corona discharges, we investigated the polarization in the P(VDF-TrFE) layer. Poling parameters such as electric field, poling time and distance between cable and corona needle were varied. The resulting polarization was characterized with measurements of polarization profiles across the layer thickness. The poling process developed here leads to good piezoelectric properties of the cable layer. Finally, discuss the sensor properties of the cable.","PeriodicalId":331115,"journal":{"name":"Proceedings. 11th International Symposium on Electrets","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131681609","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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