{"title":"Preparation of porous PTFE/PE/PP composite electret and study of its charge storage stability","authors":"S. Song, J. Jiang, L. Cui, X.P. Wang, Z. Xia","doi":"10.1109/ISE.2005.1612319","DOIUrl":"https://doi.org/10.1109/ISE.2005.1612319","url":null,"abstract":"In this paper we introduced the preparing process and corona charging method of the porous PTFE/PE/PP composite electret film, and furthermore, studied its charge storage stability by using the method of isothermal surface potential decay measurement, open-circuit thermally stimulated discharge current spectra. It was shown that 1) charge storage stability for negative porous PTFE/PE/PP composite electret corona charged at high temperature was almost the same as that of porous PTFE electret charged at room temperature. 2) The charge storage stability of porous PTFE/PE/PP electret was closely related to the structure of porous PTFE and charging condition. 3) Porous PTFE/PE/PP electret exhibited higher charge storage stability than porous PTFE electret under high humidity.","PeriodicalId":364651,"journal":{"name":"2005 12th International Symposium on Electrets","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132024051","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":"Electret properties in hybrid film consisting of porous PTFE and PP with negative corona charging","authors":"G. Chen, H. Xiao, Z. Xia","doi":"10.1109/ISE.2005.1612318","DOIUrl":"https://doi.org/10.1109/ISE.2005.1612318","url":null,"abstract":"In this work the electret properties of hybrid film consisting of porous PTFE and PP, which come from Shanghai Dagong new materials Co. Ltd., are investigated by means of corona charging, open-circuit thermally stimulate discharge (TSD ) analysis and isothermal surface-potential decay measurement. The results indicate that there are space charge and polar charge for the hybrid film consisting of PP and porous PTFE charged by means of corona discharge method. When charging is through PP side, the space charge carriers are mainly trapped in PP layer and on the interface between PP and PTFE layers. The difference of TSD current spectra between the hybrid film consisting of PP with different physical appearance is very large. For PP materials the crystallites are the main source of space charge traps. The electric field generated by space charge can cause polarization of polymer and give birth to polar charge. The wider TSD current peaks are probably due to different structural traps originating from the mixture of two crystalline morphology PP.","PeriodicalId":364651,"journal":{"name":"2005 12th International Symposium on Electrets","volume":"96 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132101821","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":"Electrostatic investigation of charged nanoporous electret materials","authors":"Wen-liang Liu, Dar-Ming Chiang, Jen-Luan Chen, Ryoichi Susuki","doi":"10.1109/ISE.2005.1612312","DOIUrl":"https://doi.org/10.1109/ISE.2005.1612312","url":null,"abstract":"The electret properties of nano and/or meso porous fluoropolymer mats and films, fabricated by impregnation and super-critical fluids (SCFs) method and charged by the corona method at ambient environment, are investigated. Positron annihilation lifetime spectroscopy (PALS) and small angle X-ray scattering (SAXS) are applied to study the charge characteristics of a free volume of electret polymeric materials. The topography and surface charges of electret polymeric materials are studied by electric field microscopy (EFM). The experimental results reveal that the nanopores and/or mesopores of the electret polymeric materials influence the retention and stability of charge. Aged surface charges were enhanced by more than ten times from comparisons with and without fluoro-polymer impregnation of the PP mat.","PeriodicalId":364651,"journal":{"name":"2005 12th International Symposium on Electrets","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129186549","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":"The pyroelectric coefficient of composites","authors":"B. Ploss, S. Kopf, F. G. Shin","doi":"10.1109/ISE.2005.1612431","DOIUrl":"https://doi.org/10.1109/ISE.2005.1612431","url":null,"abstract":"The effective physical properties of composites are generally depending on the properties of the constituents, the volume ratio, and the shape and spatial arrangement of the components (e.g. the connectivity) in a quite complex way. This is the reason why problems like the dielectric constant of composites have kept scientists busy over more than a century. In the case of properties like the pyroelectric coefficient we have derived a simple relation which is of universal validity if only the following assumption is accepted: the dielectric constants of the constituents do not change under the influence of the electric field generated by the pyroelectric activity. This assumption holds usually very well in pyroelectric materials, as the electric field which results from the pyroelectric activity is much smaller than the electric field required to induce a significant variation of the dielectric constant. In this general relation, the pyroelectric coefficient of the composite is written as a function of the pyroelectric coefficients and dielectric constants of the constituents, the volume ratio and the effective dielectric constant of the composite material. Shape and spatial arrangement of the components are not directly involved in the relation, the influence of these is all included in the effective dielectric constant of the composite. Therefore, this relation gives a correct description for all kinds of connectivities and gives an easy access to the optimization of pyroelectric composites, e.g. by the specific introduction of some conductivity into the materials.","PeriodicalId":364651,"journal":{"name":"2005 12th International Symposium on Electrets","volume":"742 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133948371","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}
E. Piovesan, A. Marletta, M. L. Vega, A. A. Hidalgo, R. Faria
{"title":"Influence of the thickness and thermal treatment on absorbance, emission and surface morphology properties of self-assembly PPV films","authors":"E. Piovesan, A. Marletta, M. L. Vega, A. A. Hidalgo, R. Faria","doi":"10.1109/ISE.2005.1612442","DOIUrl":"https://doi.org/10.1109/ISE.2005.1612442","url":null,"abstract":"In this report we studied the effect of the thickness and thermal conversion of poly(p-phenylene vinylene) (PPV) films on the optical properties. Self-assembly PPV films were processed with 5 and 75 layers from PPV precursor polymer and dodecylbenzenesulfonate. The thermal conversion treatment was performed at 110 /spl deg/C and 230 /spl deg/C. The emission spectra show a red shift when the film thickness increases; demonstrating the influence of substrate/film interface. Strong anisotropy is observed with 5 layer films (0.57), this value decrease to 0.36 with 75 layers and converted at 230 /spl deg/C. The film surface topology was available using Atomic Force Microscopy aimed at identifying morphology changes in SA-PPV films.","PeriodicalId":364651,"journal":{"name":"2005 12th International Symposium on Electrets","volume":"321 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132329176","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":"Recent developments of piezoelectric polymers - polyurea, odd-nylon, vinylidenecyanide copolymer, and polylactic acid","authors":"E. Fukada","doi":"10.1109/ISE.2005.1612330","DOIUrl":"https://doi.org/10.1109/ISE.2005.1612330","url":null,"abstract":"Polyvinylidene fluoride and its copolymers are well known piezoelectric polymers. Besides these a number of piezoelectric polymers have been investigated. Thin films of polyurea are synthesized by vapor deposition polymerization in vacuum and the piezoelectric constant of aromatic polyurea is d/sub 31/ = 10 pC/N, which is stable until 200/spl deg/C. Odd-numbered nylons exhibit the field-induced rotation of the hydrogen-bonded molecular sheets. The piezoelectric constant increases above the glass transition temperature (d/sub 31/ = 17 pC/N). Vinylidene cyanide/vinylacetate copolymers are non-crystalline polymers and show the piezoelectric constant d/sub 31/ = 10 pC/N after poling above the glass transition temperature. The large dielectric relaxation strength results in the large remanent polarization. Elongated films of helical polylactic add show the shear piezoelectric constant d/sub 14/ = -10 pC/N. Strong optical activity and biodegradation are noticeable. All these polymers show the ferroelectric hysteresis and polarization reversal.","PeriodicalId":364651,"journal":{"name":"2005 12th International Symposium on Electrets","volume":"44 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122427966","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":"Factors governing ferroelectric switching characteristics in thin films of VDF/TrFE copolymers","authors":"T. Furukawa, T. Nakajima, Y. Takahashi","doi":"10.1109/ISE.2005.1612335","DOIUrl":"https://doi.org/10.1109/ISE.2005.1612335","url":null,"abstract":"Ferroelectric switching characteristics of the thin films of vinylidene fluoride (VDF)/trifluoroethylene (TrFE) copolymer depend on a variety of factors such as the strength, pulse width and repetition of the applied electric field, as well as crystallinity, film thickness and electrode species. We present the results of a series of switching measurements for the VDF/TrFE copolymer thin films and discuss their implications in relation to their structures and the nucleation-growth mechanism.","PeriodicalId":364651,"journal":{"name":"2005 12th International Symposium on Electrets","volume":"80 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127500679","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":"The time as a parameter to investigate the landscape of the apparent activation energies in the final thermally stimulated discharge current measurements","authors":"E. Neagu, R. Neagu, M. Lança, J. Marat-Mendes","doi":"10.1109/ISE.2005.1612379","DOIUrl":"https://doi.org/10.1109/ISE.2005.1612379","url":null,"abstract":"The experimental results obtained in a wide range of temperatures, for polyethylene terephthalate, demonstrate that the apparent activation energy changes when the charging (polarization) time or the isothermal discharging time, prior to the final thermally stimulated discharge current measurement, are used as variable parameters. Consequently, the charging and/or discharging time can be used as a variable parameter to investigate the landscape of the apparent thermal activation energies. A continuous distribution of the traps in the range from 0.4 to 3 eV was observed. The experimental results demonstrate that there is a range of experimental conditions for which the thermal activation energy is independent of the experimental parameter values. This is the activation energy value which should be used to characterize a certain mechanism.","PeriodicalId":364651,"journal":{"name":"2005 12th International Symposium on Electrets","volume":"756-759 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122011978","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 detrapping behavior in different crystal phase of nylon 11","authors":"J. Zhu, X.Y. Zhang, B. He","doi":"10.1109/ISE.2005.1612371","DOIUrl":"https://doi.org/10.1109/ISE.2005.1612371","url":null,"abstract":"Thermally stimulated depolarization current (TSDC) measurement has been used to investigate the space charge detrapping behavior in four kinds of nylon 11 samples (melt-quenched, melt-annealed, solution-cast and solution-cast and then annealed). There are four space charge detrapping processes in TSDC spectra of melt-quenched and solution-cast samples. On annealing, the high temperature peak will disappear because the defects in crystalline lamellas disappear and there are only two partly overlapped space charge peaks in the TSDC spectra of well annealed sample. Various local energy levels have a trend of becoming close to each other.","PeriodicalId":364651,"journal":{"name":"2005 12th International Symposium on Electrets","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116984314","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":"An explanation of the large peak of activation energy observed by TSDC at T/sub g/: a simple model of entropy relaxation","authors":"J. Bisquert, F. Henn, J. Giuntini","doi":"10.1109/ISE.2005.1612389","DOIUrl":"https://doi.org/10.1109/ISE.2005.1612389","url":null,"abstract":"When investigating amorphous materials, i.e. polymers and glasses, by Thermally Stimulated Depolarization Current (TSDC), strong changes in relaxation rates at the glass transition T/sub g/ are frequently explained in terms of a physical singularity of the molecular motions. We show that the unexpected values for activation energy and pre-exponential factor obtained around T/sub g/ from the analysis of TSDC signal, result from the misuse of the Arrhenius law for treating the experimental data obtained in non-stationary experimental conditions. A simple model based on a time dependent configurational entropy is therefore proposed to explain the experimental behavior. Then, the pronounced variation of the effective activation energy appears as a dynamic signature of a simple entropy relaxation associated to non-stationary conditions.","PeriodicalId":364651,"journal":{"name":"2005 12th International Symposium on Electrets","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115662332","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}