9 documents found, page 1 of 1
Photopyroelectric spectroscopy of polyaniline films
De Albuquerque, J. E.; Melo, W. L.B. [UNESP]; Faria, R. M.Made available in DSpace on 2022-04-28T19:54:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2000-05-15; Photopyroelectric spectroscopy (PPES), in the 400<λ<900 nm wavelength range, was used to study thermal properties of differently doped polyaniline (PAN) films. The photopyroelectric intensity signal Vn(λ) and its phase Fn(λ) were independently measured, as well as the intensity Vn(f) and the phase Fn(f)...
Influence of Moisture In Step-voltage Measurements of PVDF
Faria, R. M.; Nogueira, J. S.; Alves, N. [UNESP]Made available in DSpace on 2022-04-28T18:54:01Z (GMT). No. of bitstreams: 0 Previous issue date: 1992-10-14; Step-voltage current measurements carried out with commercial poly(vinylidene fluoride) (PVDF) under vacuum showed a prominent peak in the charging current when a sample had previously been in contact with a humid environment. This effect tends to disappear in subsequent measurements performed under the...
Thermal-history-dependent transition in pressed pellets of ClO4 - Doped poly(3-...
Pereira, E. C.; Bulhoes, L. O.S.; Pawlicka, A.; Nascimento, O. R.; Faria, R. M.; Walmsley, L. [UNESP]Made available in DSpace on 2022-04-28T19:53:33Z (GMT). No. of bitstreams: 0 Previous issue date: 1994-01-01; Electron-spin-resonance and dc conductivity data show a thermal-history-dependent transition at 240 K in pressed pellets of ClO4 - doped poly(3-methylthiophene) (P3MT). We discuss the possibility of this transition to be a Peierls transition from a room-temperature-metallic to a charge-density-wave stat...
Electrical properties of electrochemically doped organic semiconductors using l...
Gozzi, G. [UNESP]; Cagnani, L. D.; Faria, R. M.; Santos, L. F. [UNESP]Made available in DSpace on 2018-12-11T17:02:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-08-01; We present a study of the electrical properties of electrochemically doped conjugated polymers using polymeric light-emitting electrochemical cells (PLECs) and interpreting the results according to a phenomenological model (PM) which assumes that, above the device turn-on voltage, the bulk transport pro...
Study of optical absorption differences of doped polyaniline films by photother...
Albuquerque, J. E. de; Melo, W. L. B.; Faria, R. M.In this work, we studied the optical absorption spectral differences between doped and slightly doped polyaniline films and a derivative by photopyroelectric and photoacoustic spectroscopies. There exist great spectral differences between doped and slightly doped samples as shown by conventional optical absorption spectroscopy, but not greatly evidenced by photopyroelectric spectroscopy. The latter was applied ...
Quantitative depth profile study of polyaniline films by photothermal spectrosc...
Albuquerque, J. E. de; Balogh, D. T.; Faria, R. M.In this study, we carried out a quantitative depth profile analysis of the optical properties of slightly and strongly doped polyaniline (PANI) films, using both photoacoustic and photopyroelectric spectroscopies. As the thermal diffusion length varies inversely to chopper modulation frequency, then at high chopping frequencies information about the sample near the surface is obtained, while at low chopping fre...
Surface morphology and optical characterization of OC1 OC6-PPV films
Marletta, A.; Olivati, C. A. [UNESP]; Ferreira, M. [UNESP]; Vega, M. L.; Balogh, D. T.; Faria, R. M.; Oliveira Jr., O. N.Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T19:01:26Z No. of bitstreams: 1 S0103-97332006000300070.pdf: 269695 bytes, checksum: b91deb39b4a0b9663e34c83442d65542 (MD5); Made available in DSpace on 2013-08-22T19:01:26Z (GMT). No. of bitstreams: 1 S0103-97332006000300070.pdf: 269695 bytes, checksum: b91deb39b4a0b9663e34c83442d65542 (MD5) Previous issue date: 2006-06-01; Made availabl...
Electrode poling of cellular polypropylene films with short high-voltage pulses
Gerhard-Multhaupt, Reimund; Wegener, M.; Wirges, W.; Giacometti, J. A. [UNESP]; Altafim, R. A C; Santos, L. F.; Faria, R. M.; Paajanen, M.Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:20:23Z No. of bitstreams: 0; Made available in DSpace on 2014-05-27T11:20:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2002-01-01; Recently, piezoelectric cellular polypropylene (PP) was proposed as a new type of quasi-ferroelectric. The observed hysteresis of the charge density as a function of the electric field...
Stable and metastable ferroelectric polarization analyzed by the ramp voltage t...
Wisniewski, C.; Leal Ferreira, G. F.; Faria, R. M.; Giacometti, J. A. [UNESP]Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-27T11:20:32Z No. of bitstreams: 0; Made available in DSpace on 2014-05-27T11:20:32Z (GMT). No. of bitstreams: 0 Previous issue date: 2002-12-01; The study of the stable and the metastable ferroelectric polarization of poly(vinylidene fluoride), PVDF, was performed using two successive equal sign ramp voltages, mediated by a sho...