Diffusion and Permeability
Diffusion and mass transfer plays a significant role in a material’s performance and stability. Gases and vapors interact and exchange with a surface altering its external interfaces and internal bulk composition. The ability to closely monitor diffusion processes is essential to determine important characteristics like product lifetime and exchange efficiency. Permeability and vapor uptake are of interest to many industrial sectors such as packaging materials, pharmaceuticals, membrane technology, food, and cosmetics.
Blister packaging systems are often used as the primary barrier against vapor and liquids in moisture-sensitive products such as those used in the pharmaceutical industry. These blister packaging systems often show substantial differences in barrier properties to the unformed polymer film due to localized defects/stresses in the polymer material as a result of the forming process. Their diffusion and permeability performance can be studied, measured, and evaluated in detail using the DVS method.
Application Note 12: Absolute Measurement of Moisture Diffusion into Blister Packaging Systems | Request a copy
Analyzing the diffusion and permeation of moisture through real packaging devices is crucial for the development of food packaging solutions. Typical requirements for food packaging systems state that the loss of moisture over long storage periods must be kept to a minimum to prolong the shelf life of the product. The DVS technique can be used to rapidly assess the kinetics of moisture loss to predict material stability.
Application Note 07: Measurement of Diffusion of Liquids and Vapors Through Real Polymer Tube Packaging Devices | Request a copy
The microelectronics industry continues to create devices that are more powerful, reliable, and economical. A key feature in many devices is the packaging system used to protect the device from physical damage and environmental degradation. Hermetically sealed packages are the preferred solution for high-cost, high-reliability applications such as avionics and defense. A more cost-effective solution is required for consumer and industrial applications. The common packaging solution used today is to encapsulate the device and interconnection system in a thermosettable polymer resin. These can be studied at high temperatures and humidity using the DVS.
Application Note 31: Measurement of Moisture Ingress in Microelectronics Device Packaging | Request a copy
Polymers and Packaging
Moisture diffusion in thin polymer films is imperative to packaging materials and membrane technologies. The diffusion equations that are used to calculate diffusion constants for thin films were first employed by Crank and Park. A thin film sample suspends in the DVS and the sorption kinetics for a series of steps in humidity are recorded in the usual manner. Dynamic Vapor Sorption (DVS) is a valuable technique when measuring isotherms in polymers.
Application Note 30: Calculation of Diffusion Constants in Thin Polymer Films using DVS | Request a copy
Vapor permeability plays an important role in porous materials such as membrane technologies. Moisture vapor transmission measurements are generally carried out under isothermal conditions. MVTR describes the rate of water permeating through a test specimen into the headspace volume of a container which differs in relative humidity (ΔRH). Dynamic – vapor sorption (DVS) is a well-established method that can be used to determine the MVTR of porous materials. The high mass resolution and excellent baseline stability of DVS allows for fast and accurate determination of water sorption isotherms and diffusion kinetics over a wide range of temperatures and humidities.
Application Note 52: Vapor Permeability of Porous Materials using Payne Diffusion Cell | Request a copy
Personal Care Products
The permeability and diffusion rates of various personal care should be measured under different conditions to assess the essential characteristics. The effect of skin creams, for example, can be evaluated to test their ability to act as occlusives by observing their Transepidermal Water Loss (TEWL) or moisture flux. Payne diffusion cell coupled with the DVS instrument can be a very useful tool in measuring TEWL and moisture flux in skincare products.
Application Note 56: Measuring TEWL or Moisture Flux Across Artificial Skin | Request a copy
Determining polymer solvent swelling and interactions with DVS & iGC
Our range of DVS & iGC products are compatible to test polymer solvent swelling and interactions. View the range using the link below to find out more about which instrument is right for you.