Study of the viability of poly(o-methoxyaniline) layer-by-layer films as gas sensors

Maria Raposo, Osvaldo N. Oliveira

Research output: Contribution to journalConference articlepeer-review


The electrical properties of layer-by-layer films of poly(o-methoxyaniline) (POMA) alternated with poly(vinylsulfonic acid) (PVS) have been investigated as a function of the surrounding atmosphere, in order to probe the sensitivity of POMA/PVS as a gas sensor. The POMA films have their conductivity increased with increasing humidity, near to one order of magnitude higher for 100% relative humidity when compared to nitrogen. The d.c. applied field may affect the POMA films, for these films become practically insulating if the field is applied for a prolonged time (typically 10-20 h) in humid air. In order to circumvent this problem, a.c. impedance measurements were conducted. For samples in nitrogen, oxygen and carbon dioxide, the real part of the complex impedance increases only when the frequency is lowered below 10 kHz. In a humid atmosphere, the onset for the real part occurs at higher frequencies than for dry atmospheres. Furthermore, at a fixed frequency in the range from 10 to 100 kHz this impedance component increases with the relative humidity.

Original languageEnglish
Pages (from-to)345-350
Number of pages6
JournalMaterials Research Society Symposium Proceedings
Publication statusPublished - 2000
EventThe 1999 MRS Spring Meeting - Symposium B 'Flat-Panel Displays and Sensors-Principles, Materials and Processes' - San Francisco, United States
Duration: 4 Apr 19999 Apr 1999


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