For many years, Building Materials at Lund University has been specialists in material properties related to water and water vapor and our laboratory is very well equipped for measurements of such properties. Below follows a list of the equipment in our sorption and transport laboratory.

Sorption balances*

We have six high end sorption balances from Surface Measurement Systems Ltd:

• one DVS 1000
• two DVS Advantage both equipped with 0.1 µg Cahn microbalances
• two DVS Intrinsic
• one DVS Resolution

With these versatile instruments we mainly measure sorption isotherms, but we also use them for, e.g., measurements of transport coefficients, hydroxyl accessibility and film formation.

• Example of measurements of sorption isotherms (Research Portal)
• Article about measurements of transport coefficients (Research Portal)
• Example of measurements of hydroxyl accessibility (Research Portal)
• Example of measurements of film formation (Research Portal)

Jar method (sorption isotherms)* 

This is a low tech set-up for measuring sorption isotherms in which each sample is suspended in a glass jar with a saturated salt solution that produces a fixed RH. It is also suitable for small samples as one can weigh the samples without opening the jars.

More information about the jar method (Research Portal)

Box method (sorption isotherms)*

For larger samples – for example of concrete – we equilibrate the samples over saturated salt solutions in boxes equipped with fans.

RH-sensors

We have a large number of different types of RH-sensors, from hand-held devices to standalone loggers that can collect RH and temperature data. We calibrate these sensors in our Thunder climate chamber.

Thunder climate chamber (RH-sensor calibration)

Our Thunder climate chamber (Thunder Scientific Corporation Model 2500) is a two-pressure device traceable to NIST/NPL in which we calibrate RH-sensors, both our own and sensors belonging to consultants and other external customers.

More information about the Thunder Scientific Corporation Model 2500 (Thunder Scientific webpage)

Cup method (diffusion coefficients)

In the cup method a sample is placed as a lid on a cup containing a saturated salt solution with a fixed RH. When the cup is placed in another fixed (external) RH the measured mass loss rate of the cup is proportional to the diffusion coefficient. We have two types of cups for steady-state measurements of diffusion coefficients. One is made of polypropylene and is possible to open, enabling changing/refilling of the salt solution, and the other is made from glass. In both methods the disk shaped samples are fastened to the cup with water impermeable sealants.

More information about the cup method (Research Portal)

Pressure plate laboratory

We have a unique, custom built pressure plate laboratory with 20 small pressure plate cells which can be used to condition samples to high moisture states. The maximum pressure of these cells are 5 bar, which corresponds to a relative humidity of 99.63%.

More about the custom built pressure plate system (Research Portal).

In addition, we have five pressure extractors from SoilMoisture Equipment Corp. with the following maximum pressures: 100, 15 and 5 bar.

Climate rooms

Together with other divisions in our building we have several climate rooms (some only temperature controlled; others with both temperature and RH control). In these we can – for example – do cup measurements.

Sorption calorimeters

A unique instrument to study sorption phenomena with is the SORP sorption calorimeters that have been developed at the division. These instruments are mainly used for pharmaceutical substances, polymers and bio-molecules.

Information about sorption calorimetry (Research Portal)
More about applications of sorption calorimetry (Research Portal)

* The three methods to measure sorption isotherms all have their advantages and disadvantages. The sorption balances are normally used for small (10-100 mg) samples, the jar method for larger samples (10 g), while the box method is suitable for even larger samples. When we have many samples, the jar and box methods are used, as one with these methods can run many samples in parallel. The sorption balances have the advantage of being able to produce complex RH-schedules, for example for scanning studies.