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Miniaturized Two-level Controller Based on Moisture-sensitive Hydrogels

Authors:
Arndt Steinke
Thomas Frank
Andrea Cyriax
Christian Bellmann
Gerald Gerlach
Helmut F. Schlaak
Reza Sarwar

Keywords: binary sensor switch; relative humidity; zero-power; boss structure; hydrogel (PVA / PAAs)

Abstract:
In this paper, we present a novel binary threshold sensor, which is able to use the energy provided directly from the measured relative humidity of the ambient air to mechanically switch an electrical micro contact. This zeropower switch behavior is realized by using the humiditysensitive volume swelling of a polymer layer as the detection element deflecting a mechanical deformable silicon boss structure, thus closing the electrical contacts of the switch. For the humidity-sensitive sensor switch considered here, a hydrogel blend of 15 wt% poly(vinyl alcohol) (PVA) and 7.5 wt% poly(acryl acid) (PAA) was used. According to first swelling experiments with a prototype the provided deflection of approximately 36 μm of a 20 μm thin silicon flexure plate seems very promising.

Pages: 75 to 79

Copyright: Copyright (c) IARIA, 2013

Publication date: August 25, 2013

Published in: conference

ISSN: 2308-3514

ISBN: 978-1-61208-297-4

Location: Barcelona, Spain

Dates: from August 25, 2013 to August 31, 2013