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Method to study water diffusion into polymers

: Boudaden, Jamila; Steinmaßl, Matthias; Endres, Hanns-Erik; Müller-Buschbaum, Peter

Fulltext urn:nbn:de:0011-n-5256249 (682 KByte PDF)
MD5 Fingerprint: 02c93de0d18e3e227c26b94bb83464dd
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Created on: 9.1.2019

Proceedings. MDPI AG 2 (2018), No.13, Art. 812, 4 pp.
ISSN: 2504-3900
Eurosensors Conference <32, 2018, Graz>
Journal Article, Conference Paper, Electronic Publication
Fraunhofer EMFT ()
polyimide; relative humidity sensor; interdigitated transducer IDTs; thermal stress; thermoresponsive polymer

We designed and realized a low cost relative humidity (RH) capacitive sensor having an interdigitated transducer coated with a cheap sensing material working at room temperature (polyimide). Thermally perturbed diffusion of water molecules into the polyimide layer is studied by heating the sensor locally and measuring the sensor capacitance change. The swelling and deswelling model is applied to determine the time constant of involved processes. This simple method, using an evaluation kit developed by our group, to measure the sensor capacitance and to study the diffusion process of water molecules into polyimide could be generalized to analyze the gas diffusion processes into polymer based sensing layer generally used in the field of gas chemical sensors.