Proceedings. 11th International Symposium on Electrets最新文献_第10页

Dielectric properties of polymers with fractal architecture 分形结构聚合物的介电性能

Proceedings. 11th International Symposium on Electrets Pub Date : 2002-12-10 DOI: 10.1109/ISE.2002.1042947

É. Dantras, A. Caminade, J. Majoral, C. Lacabanne

引用次数: 0

Dielectric characterization of PEBA and PDMS for capacitive interdigital vapour sensors

Proceedings. 11th International Symposium on Electrets Pub Date : 2002-12-10 DOI: 10.1109/ISE.2002.1042998

R. Igreja, J. Marat-Mendes, C. Dias

{"title":"Dielectric characterization of PEBA and PDMS for capacitive interdigital vapour sensors","authors":"R. Igreja, J. Marat-Mendes, C. Dias","doi":"10.1109/ISE.2002.1042998","DOIUrl":"https://doi.org/10.1109/ISE.2002.1042998","url":null,"abstract":"During the wine fermentation process the aroma profile produced is very complex and changes notably due to the yeast metabolism, while ethanol is produced simultaneously in much higher concentrations (up to 10 wt.%) relatively to aroma compounds (in the ppm range), making very difficult to follow the aroma profile with the conventional sensors. An automated aroma sensing system for the wine-must fermentation may render possible to detect and correct undesired off-flavors, representing major losses for the wine-industry. We are developing an Interdigital Capacitor (IDC) sensor array to be part of an electronic nose for on-line and real-time monitoring of wine fermentation process. The basic transducer has an interdigital electrode configuration (typical gap and finger of 100 /spl mu/m) made on a glass substrate coated with a polymer sensitive layer. We had developed an analytical model for the interdigital geometries to predict the capacitance in accordance with the geometry of the electrodes and the change of capacitance with the change of permittivity and thickness of the sensitive layer. Numerical simulation of the sensors geometry has been made for the validation of the analytical model. The capacitance measured for the sensors are in good agreement with our analytical model. Polydimethylsiloxane (PDMS) and polyetherblockamide (PEBA) have been chosen for the sensitive layer and are characterized.","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":"125945649","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}

引用次数: 5

Polarization of porous PE foil 多孔PE箔的极化特性

Proceedings. 11th International Symposium on Electrets Pub Date : 2002-12-10 DOI: 10.1109/ISE.2002.1042980

R. Kacprzyk

引用次数: 3

Preparation of electrets by interlayer polarization methods 层间极化法制备驻极体

Proceedings. 11th International Symposium on Electrets Pub Date : 2002-12-10 DOI: 10.1109/ISE.2002.1042970

C. Wang, J. Li, Y. Liu, J. Xu, Z. Wu, C. X. Sun

引用次数: 0

Dielectric relaxations in ultra-thin films of PMMA: assessing the length scale of cooperativity in the dynamic glass transition PMMA超薄膜中的介电弛豫:动态玻璃化转变中协同性长度尺度的评估

Proceedings. 11th International Symposium on Electrets Pub Date : 2002-12-10 DOI: 10.1109/ISE.2002.1043027

M. Wubbenhorst, C. Murray, J. Forrest, J. Dutcher

{"title":"Dielectric relaxations in ultra-thin films of PMMA: assessing the length scale of cooperativity in the dynamic glass transition","authors":"M. Wubbenhorst, C. Murray, J. Forrest, J. Dutcher","doi":"10.1109/ISE.2002.1043027","DOIUrl":"https://doi.org/10.1109/ISE.2002.1043027","url":null,"abstract":"The local and cooperative dynamics of supported ultra-thin films (L = 4-170 nm) of poly(methyl methacrylate) was investigated by dielectric spectroscopy at frequencies from 0.1 Hz to 10/sup 6/ Hz and temperatures from 250-423 K. To assess the effect of stereoregularity, three tacticities (i, a and s-PMMA) of similar molecular weight M/sub n/ = 120-140/spl times/10/sup 3/ g mol/sup -1/ were studied. A second M/sub n/ value for s-PMMA was also studied. For i-PMMA, a decrease of the glass transition temperature T/sub g/ by up to 10 K was observed for a film thickness L < 25 nm (which is comparable to R/sub EE/), indicated by a down-shift of the peak temperature T/sub /spl alpha// in the loss /spl epsiv/\"(T) at low and high frequencies and by a shift of the maximum in the apparent activation energy E/sub a/(T) of the /spl alpha/-process. Changes in the relaxation strength and the peak shape are apparent for L /spl les/ 50 nm. In addition, the /spl beta/-relaxation probing the local mobility was investigated for i-, a- and s- PMMA. Interestingly, all polymers revealed a systematic speedup in the local dynamics for L < 25 nm which is accompanied by systematic changes in the relaxation strength. For i-PMMA, a clear relation between the thickness dependence of /spl tau//sub /spl beta// and /spl tau//sub /spl alpha// was found indicating that thickness dependences in the cooperative dynamics are predominantly induced by changes in the local mobility. These findings are consistent with the idea of confinement induced changes in the orientation and conformation statistics for thicknesses below R/sub EE/.","PeriodicalId":331115,"journal":{"name":"Proceedings. 11th International Symposium on Electrets","volume":"89 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":"132828684","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}

引用次数: 15

Piezoelectric films for MEMS applications 用于MEMS应用的压电薄膜

Proceedings. 11th International Symposium on Electrets Pub Date : 2001-05-01 DOI: 10.1109/ISE.2002.1043025

F. Xu, R. Wolf, T. Yoshimura, S. Trolier-McKinstry

引用次数: 37