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Lanthanide-halide based humidity indicators

United States Patent

January 1, 2008
View the Complete Patent at the US Patent & Trademark Office
Argonne National Laboratory - Visit the Technology Development and Commercialization Website
The present invention discloses a lanthanide-halide based humidity indicator and method of producing such indicator. The color of the present invention indicates the humidity of an atmosphere to which it is exposed. For example, impregnating an adsorbent support such as silica gel with an aqueous solution of the europium-containing reagent solution described herein, and dehydrating the support to dryness forms a substance with a yellow color. When this substance is exposed to a humid atmosphere the water vapor from the air is adsorbed into the coating on the pore surface of the silica gel. As the water content of the coating increases, the visual color of the coated silica gel changes from yellow to white. The color change is due to the water combining with the lanthanide-halide complex on the pores of the gel.
Beitz; James V. (Hinsdale, IL), Williams; Clayton W. (Chicago, IL)
U.S. Department of Energy (Washington, DC)
10/ 839,203
May 6, 2004
U.S. GOVERNMENT RIGHTS The United States Government has rights in this invention pursuant to Contract No. W-31-109-ENG-38 between the U.S. Department of Energy and the University of Chicago, representing Argonne National Laboratory.