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Polymer Sensor Provides Record of Percent Relative Humidity Exposure

IP.com Disclosure Number: IPCOM000107896D
Original Publication Date: 1992-Mar-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 1 page(s) / 28K

Publishing Venue

IBM

Related People

Gross, VP: AUTHOR [+2]

Abstract

A relative humidity detector is described that is based on the electrical properties of a polymer film. In its uncharged state, polyaniline-polystyrene sulfonic acid co-polymer film exhibits green color and electrical conductivity. After the film is charged by a relatively high voltage, the film turns blue and becomes non-conductive. The film will retain these characteristics after the charging voltage is disconnected if the relative humidity is very low. If the charged film is exposed to humidity, it becomes hydrated, turns green and becomes conductive again. The green, conductive characteristics are retained even though the humidity returns to a very low value. This process is found to be continuously repeatable, and the film may be re-used if it is electrically re-charged.

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Polymer Sensor Provides Record of Percent Relative Humidity Exposure

      A relative humidity detector is described that is based on the
electrical properties of a polymer film.  In its uncharged state,
polyaniline-polystyrene sulfonic acid co-polymer film exhibits green
color and electrical conductivity.  After the film is charged by a
relatively high voltage, the film turns blue and becomes
non-conductive.  The film will retain these characteristics after the
charging voltage is disconnected if the relative humidity is very
low.  If the charged film is exposed to humidity, it becomes
hydrated, turns green and becomes conductive again.  The green,
conductive characteristics are retained even though the humidity
returns to a very low value.  This process is found to be
continuously repeatable, and the film may be re-used if it is
electrically re-charged.

      Disclosed anonymously.