9th International Symposium on Electrets (ISE 9) Proceedings最新文献

{"title":"Dielectric relaxation in PVDF, P(VDF-TFE) and PVDF-BaTiO/sub 3/ composites","authors":"S. Fedosov, A. Sergeeva, P. Pissis, J. Marat-Mendes","doi":"10.1109/ISE.1996.578223","DOIUrl":"https://doi.org/10.1109/ISE.1996.578223","url":null,"abstract":"Summary form only given. Relaxation processes in ferroelectric polymer-ceramic composites are not a simple superposition of those observed in pure components. In our case, pure PVDF, P(VDF-TFE) copolymer and PVDF-BaTiO/sub 3/ composite were studied by the thermally stimulated depolarization (TSD) method from -160/spl deg/C to +100/spl deg/C and by the AC dielectric spectroscopy method from -60/spl deg/C to +100/spl deg/C at frequencies from 100 Hz to 5 MHz. Polymer films were extruded and stretched, while composite samples were prepared by hot pressing of PVDF powder mixed with BaTiO/sub 3/ particles in equal volume proportion. Three relaxation processes were identified, namely /spl alpha/-relaxation in amorphous phase of PVDF and P(VDF-TFE) related to the glass transition, /spl beta/-relaxation in the glassy state of the polymer and the interfacial or space charge relaxation at 60-100/spl deg/C. A non-Debye TSD /spl alpha/-peak around -45/spl deg/C indicated that there was a broad distribution of relaxation times. The same process gave rise to a peak at the frequency dependence of imaginary part of the dielectric constant during the AC dielectric measurements. The peak in PVDF-BaTiO/sub 3/ composite appeared at -20/spl deg/C and 50 kHz compared to 30 kHz in pure PVDF, showing a weak anti-plasticizing effect of the filler. Our experimental data were fitted to Cole-Davidson and Havriliak-Negami theoretical expressions and corresponding distribution parameters were obtained. The /spl alpha/-relaxation was believed to be caused by micro-Brownian motions of segments of the main polymer chain, while the /spl beta/-relaxation, seen as a broad TSD peak at -135/spl deg/C corresponded most probably to the local mode motions in the glassy state of the polymers. The space charge peak at 60-100/spl deg/C has been explained in the framework of the phenomenological model stipulating existence of charge trapping during the buildup of polarization either in crystallites in case of PVDF and copolymer, or in BaTiO/sub 3/ particles of the composite.","PeriodicalId":425004,"journal":{"name":"9th International Symposium on Electrets (ISE 9) Proceedings","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121800956","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}

{"title":"Thermally stimulated depolarization current in PVDF, P(VDF-TFE) and P(VDF-TrFE)","authors":"Z. Xia, S. Fedosov, A. Sergeeva, H. Zhang","doi":"10.1109/ISE.1996.578230","DOIUrl":"https://doi.org/10.1109/ISE.1996.578230","url":null,"abstract":"TSD currents are studied in short circuit (SC) and open circuit (OC) modes in differently poled PVDF, P(VBF-TFE) and P(VDF-TrFE). A new phenomenon is observed, namely a double inversion of the TSD current in the OC mode and appearance of two well structured peaks in the SC mode in poled samples stored for 14 months, indicating that two different kinds of polarization exist in ferroelectric polymers, both accompanied by deeply trapped charge. The more stable component of polarization has presumably a ferroelectric nature, while the less stable one is attributed to polarization in amorphous phase. It is shown that very slow processes of space charge redistribution take place in ferroelectric polymers until the quasi-stationary state is readied.","PeriodicalId":425004,"journal":{"name":"9th International Symposium on Electrets (ISE 9) Proceedings","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121912842","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}

{"title":"Space charge formation in gamma-irradiated low-density polyethylene","authors":"G. Chen, H. M. Banford, A. Davies","doi":"10.1109/ISE.1996.578068","DOIUrl":"https://doi.org/10.1109/ISE.1996.578068","url":null,"abstract":"Energetic ionising radiation can alter the chemical structure of polymeric materials and may also give rise to the presence of trapped charge within the material, the trapping characteristics of which may be influenced by these radiation-induced structural alternations. In the present work, space charge formation in irradiated low-density polyethylene (LDPE) was investigated using the laser induced pressure pulse (LIPP) technique. Specimens of LDPE, /spl sim/350 /spl mu/m thick, were irradiated in a /sup 60/Co /spl gamma/-source in air at ambient temperature to various doses and the results indicate that space charge distributions are dependent on both dose and applied electric stress and the length of time for which the stress is applied.","PeriodicalId":425004,"journal":{"name":"9th International Symposium on Electrets (ISE 9) Proceedings","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122761879","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}

{"title":"Thermally stimulated current and infrared studies of copolymer films of VDF and 5 mol.% TFE","authors":"Y. Gorokhovatsky, L. Kurennaya, D. Temnov, W. Kunstler, V. Zakrzhevsky","doi":"10.1109/ISE.1996.578219","DOIUrl":"https://doi.org/10.1109/ISE.1996.578219","url":null,"abstract":"Copolymerization of vinylidenefluoride (VDF) with tetrafluoroethylene (TFE) leads to a considerably higher /spl beta/-phase content than the copolymerization with trifluoroethylene (TrFE). This is confirmed by comparison of the IR spectra of the copolymers and the homopolymers. The IR spectra of uniaxially stretched copolymer films of VDF and 5 mol.% TFE show the absence of bands attributed to the a phase in contrast to the respective spectra of the homopolymer. Two peaks are found in the curve of the thermally stimulated current for these polymers above room temperature. An analysis of these peaks allows us to obtain a two-dimensional distribution of relaxation times (energy and frequency factors).","PeriodicalId":425004,"journal":{"name":"9th International Symposium on Electrets (ISE 9) Proceedings","volume":"26 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120816557","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}

{"title":"Piezoelectric and ferroelectric properties of aliphatic polyurea films synthesized by vapor deposition polymerization","authors":"T. Hattori, Y. Takahashi, M. Iijima, E. Fukada","doi":"10.1109/ISE.1996.578213","DOIUrl":"https://doi.org/10.1109/ISE.1996.578213","url":null,"abstract":"Thin films of aliphatic polyurea films were synthesized on the cooled substrates by vapor deposition polymerization. Poling dynamics of the films depended on the crystallinity. Polyurea-5 exhibited ferroelectric hysteresis. The maximum values of piezoelectric stress constant e/sub 31/ and pyroelectric constant p/sub 3/, obtained for polyurea-5 poled at Ep=250 MV/m, Tp=150/spl deg/C and tp=10 min, were 15 /spl mu/C/m/sup 2/K and 10 mC/m/sup 2/, respectively. Three relaxations were found similar to nylon in the temperature dependence of the elastic constant c/sub 1/, the dielectric constant /spl epsi//sub 3/ and the piezoelectric constant e/sub 31/.","PeriodicalId":425004,"journal":{"name":"9th International Symposium on Electrets (ISE 9) Proceedings","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125840693","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}

{"title":"Long-term charge stability of silicon dioxide electrets","authors":"M. Ichiya, J. Lewiner","doi":"10.1109/ISE.1996.578030","DOIUrl":"https://doi.org/10.1109/ISE.1996.578030","url":null,"abstract":"In this paper, we report the investigation of silicon dioxide electrets by using plasma chemical vapor deposition (PCVD) and thermal oxidation process. It is shown that by using a proper process, long-term charge stability can be obtained, even at elevated temperatures. Physical studies will be described, in which the charge stability is correlated to Thermally Stimulated Current (TSC) measurements and to Electron Spin Resonance (ESR) analysis. Some intrinsic differences have been observed between materials with different long-term charge stability.","PeriodicalId":425004,"journal":{"name":"9th International Symposium on Electrets (ISE 9) Proceedings","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126071804","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}

{"title":"Organization of molecules in thin polymer layers by electron beam poling","authors":"R. Danz, M. Pinnow, A. Buchtemann, A. Wedel","doi":"10.1109/ISE.1996.578122","DOIUrl":"https://doi.org/10.1109/ISE.1996.578122","url":null,"abstract":"Electron beam poling was developed and applied to thin polymer layers by use of a scanning electron microscope. Molecular manipulations of orientation of the molecules were induced by focused electron beams, and detected by means of infrared spectroscopy as well as by nonlinear optical methods. Using electron beam microlithography microscopic polarization structures have been written into thin fluoropolymer layers by means of a direct, computer-controlled writing process; they were read out through potential contrast images as well as by studies concerning second harmonic generation (SHG).","PeriodicalId":425004,"journal":{"name":"9th International Symposium on Electrets (ISE 9) Proceedings","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126321025","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}

{"title":"Poling of VDF/TrFe copolymers using a step-wise method","authors":"D. Setiadi, T. Binnie, P. Regtien, M. Wubbenhorst","doi":"10.1109/ISE.1996.578215","DOIUrl":"https://doi.org/10.1109/ISE.1996.578215","url":null,"abstract":"A new poling technique is presented, in which a series of five consecutive pulses of electric field, and with successively increasing strength is applied between the two electrodes of 65/35 VDF/TrFE copolymer based sensor. Between each pulse, the applied electric field is reduced to zero (short circuit). This allows deformations and space charges to be relax, resulting in more homogeneous electric field distribution with less risk for an electric breakdown. It is conducted at room temperature and is compatible with semiconductor technology. This step-wise poling technique is characterised by a low breakdown rate and yields a high pyroelectric coefficient.","PeriodicalId":425004,"journal":{"name":"9th International Symposium on Electrets (ISE 9) Proceedings","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126363980","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}

{"title":"Structure and grain-size distribution of TiO/sub 2//SiO/sub 2/ thin film","authors":"Zhai Jiwei, Kong Lingbing, Zhang Liangying, Y. Xi","doi":"10.1109/ISE.1996.578196","DOIUrl":"https://doi.org/10.1109/ISE.1996.578196","url":null,"abstract":"The structure and crystal grain size distribution along the thickness of TiO/sub 2//SiO/sub 2/ thin films prepared by the sol-gel process under various heat treatment temperatures were studied. The X-ray diffraction spectra demonstrate that the crystallization temperature of anatase is 660/spl deg/C for 50TiO/sub 2//50SiO/sub 2/ thin-films. At 900/spl deg/C tridymite-M and rutile structures appeared. The anatase-rutile transformation temperature is 950/spl deg/C. DTA curves show that the structural transformation of TiO/sub 2/ is a gradual process. X-ray glancing incidence analysis indicates that the crystal grain size decreases along the thickness of the thin-film. With increasing heat treatment temperature, the difference of crystal grain size along the thickness is enhanced.","PeriodicalId":425004,"journal":{"name":"9th International Symposium on Electrets (ISE 9) Proceedings","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121461951","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}

{"title":"Chemical surface modification on SiO/sub 2/ electret by DCDMS","authors":"Li Huamao, Z. Hongyan, Xia Zhongfu, Shen Shaoqun, Zhu Jianwei","doi":"10.1109/ISE.1996.578194","DOIUrl":"https://doi.org/10.1109/ISE.1996.578194","url":null,"abstract":"In this paper, an advanced study on the chemical surface modification by dichlorodimethylsilane (DCDMS) was carried out. Different cleaning processes were tried to improve the surface state of the SiO/sub 2/ film after chemical surface treatment by DCDMS. The stability of the space charges stored in these samples was investigated and the surface components of the samples were analyzed.","PeriodicalId":425004,"journal":{"name":"9th International Symposium on Electrets (ISE 9) Proceedings","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124380742","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}