National Physical Laboratory

Measurement of water sorption isotherms of materials using combined real-time humidity and microwave resonance measurements

Further Information

Published: 8 March 2012

Author: Richard Dockree

Related:  Engineering Measurement   

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Water sorption characteristics are determined for many materials normally by studying weight changes after a sample has been exposed to salt solutions of established relative humidities (e.g. COST 90 procedure).

An established technique - dynamic vapour sorption (DVS) - uses a microbalance and controlled gas flow to measure water sorption.

The water content of a material can be plotted against its water activity or the relative humidity it was exposed to producing a sorption isotherm. Hysteresis is often observed due to different adsorption/desorption characteristics of the material.

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Last Updated: 1 Apr 2014
Created: 8 Mar 2012


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