Dynamic vapor sorption (DVS)
The determination of water uptake and release is highly important for a lot of products for their application, their behavior in processes or storage issues. Water uptake can be determined as a function of relative humidity. In other projects water or other vapors are used as sensors to investigate the interaction between molecules with different polarities and surfaces and compare these interactions with other molecules. Due to practical reasons the properties of porous materials under humid conditions have to be well known.
Dynamic vapor sorption – DVS
Water vapor sorption follows the same physical rules and principles as gas sorption. The difference to gas sorption is that condensation of vapors must not influence the results of the measurement. Because of this reason, the water uptake is often measured gravimetrically in a dynamic, humid gas flow (DVS – Dynamic Vapor Sorption) – these experiments can be carried out for many materials, such as pharmaceutical products, food, packing materials, building materials etc.
Typical measurement of gravimetric water sorption experiments
Instruments
3P graviSorb Gravimetric Water Sorption Analyzer is a fully automated, gravimetric, multi-sample, high load capacity, high resolution, and dynamic water vapor sorption analyzer. It measures adsorption and desorption isotherms of water vapor both accurately and sensitively, including sorption kinetics, with minimal operator involvement. The weight of up to 12 samples is monitored and recorded as the relative humidity is automatically varied by blending dry carrier gas with a saturated gas stream. The carousel balance design of the 3P graviSorb allows increased analysis throughput by simultaneous investigation of up to 12 different samples, or 11 + 1 if one station is running an empty sample chamber or even a reference material for direct comparison. The 3P graviSorb is an ideal solution for the determination of water uptakes for research and quality assurance. The complete automatic measuring process together with the precise balance, broad climate range and user-friendly software make it the ideal instrument for high sample throughput with a minimum of costs and maintenance.
Specifications, features and benefits
- Complete automated system: automatic weighing and changing of climate according to settings of the user
- Easy-to-use, with a minimum of maintenance
- User-friendly software with advanced Excel export
- Results storage in a database with backup function
- High sample weight capacity, up to 125 g (up to 250 g as an option)
- High resolution and precision by using a 0.01 mg resolution balance
- 12 (11+1) samples can be measured simultaneously
Measurement capabilities
- Isotherms: mass change as a function of changing relative humidity, increasing mass during adsorption (increasing %RH), decreasing mass during subsequent desorption (decreasing %RH)
- Kinetics: time-dependent sorption studies give the rate of adsorption and desorption
- Effect of temperature: isotherms and kinetics change as a function of temperature. Can be used to yield sorption enthalpies.