Water Sorption Isotherms and Kinetics
The water sorption kinetics of compounds and materials are integral to their physiochemistry and stability. Measuring a water sorption isotherm with DVS provides many insights into a material’s behavior, through the classification of isotherms, examination of hysteresis, or the characterization of reversible or irreversible sorption processes.
The hydration state of materials influences several physicochemical properties including physical and chemical stability. It is especially important in the pharmaceutical industry as some hydrated materials become amorphous upon dehydration. This can affect the solubility, flowability, and dissolution rate of a compound. Approximately 1/3 of all pharmaceuticals can form hydrates so there is an increased pressure to fully characterize these hydrates, which can be achieved using DVS technology.
The kinetics of sorption can also be examined using the kinetic sorption data from DVS, this uses the integrated analysis software that easily calculates diffusion coefficients for powders and fibers. These application notes investigate the formation of hydrates in pharmaceuticals and examine how the kinetics of water sorption can be affected by an increase- in temperature.
Application Note 36: Investigation of Hydrate Formation and Loss Using the DVS | Request a copy
DVS technical Note 705: The Effect of Temperature on Moisture Sorption Kinetics in Microcrystalline Cellulose | Request a copy
The interactions of water with building materials such as cement, wood, and fibers can limit the lifespan of a building through moisture damage. Porous building materials like cement have many degradation pathways that rely on moisture present in the material. DVS can be used to study the hardening processes of building materials, the egress of water in material and outline critical relative humidity ranges for stability.
The moisture sorption uptake and kinetics of wood have been the focus of many research papers, due to the impact of sorbed moisture on wood degradation and stability. DVS can be used to distinguish between wood samples, with hysteresis in water sorption isotherms supplying valuable insight into the bulk sorption processes that occur. This application note gives an overview of the DVS method applied to building materials, and the insights it provides to the industry.
Application Note 104: Vapour Sorption Properties of Building Materials using Gravimetric Sorption Instrumentation – an Overview | Request a copy
The moisture sorption properties of food products are integral to understanding their shelf-life stability. Some foods, such as biscuits and crackers, are highly absorbent and take up high volumes of water which results in the collapse of the food structure. In countries with high humidity and temperatures, moisture stability is critical in preventing the growth of microbiological organisms which will cause food to spoil.
The DVS method can be used to measure the uptake of moisture content in food products, monitor structure collapse, investigate crystallization of products, and determine total water uptake. These application notes examine the structural stability of typical food items, coffee, and powdered milk at different relative humidity.
Application Note 11: Moisture Stability of Powdered Milk formations | Request a copy
Application Note 08: Moisture Sorption of Coffee Granules Studied using the DVS-µScope | Request a copy
Personal Care Products
The moisture sorption properties of materials in the personal care industry are examined in a variety of ways. Moisture sorption is often used as an evaluation of hair damage, where structural changes in the hair fibers result in differences in macro water management properties. Hair protection can also be measured in this way using DVS, comparing treatments with damaged samples to examine how properties of damaged hair are recovered.
In bathroom tissues, moisture sorption is important for product function, and DVS can be used to examine how different composites perform.
DVS Application Note 55: Measurement of Moisture Uptake Capacity in Human Hair Using Dynamic Vapour Sorption Technique | Request a copy
iGC-SEA & DVS Application Note 228: Water Sorption and Surface Properties of Bathroom Tissues | Request a copy
The packaging of microelectronic devices must be robust to water ingress due to the risk of ‘popcorning’ during production. Popcorning occurs when water is exposed to temperatures of over 220°C and suddenly steams causing deformation of the microelectronic structure. This can occur at moisture content levels of less than 0.1% water. Frequent testing of packaging materials is needed as devices become more powerful and get smaller.
DVS can perform water sorption measurements at elevated temperatures to mimic the real-life environments in microelectronic packaging to help understand the ‘popcorning’ effect and prevent device failure.
DVS Application Note 31: Measurement of Moisture Ingress in Microelectronics Device Packaging | Request a copy
Measuring water sorption isotherms and kinetics with DVS & iGC
Our range of DVS & iGC products were created to accurately measure water sorption isotherms and kinetics. View the ranges using the link below to find out more about which instrument is right for you.