From Particle Formation...
... To Particle Characterisation

Aquadyne DVS

Gravimetric Water Sorption Analyzer


Water sorption behavior plays an important role in the development and use of many common and advanced materials. Some examples include:

  • Stability of pharmaceutical excipients and drug actives
  • Drying and storage of grains
  • Texture and shelf life of food products
  • PEM fuel cell components
  • Mortar, grout and other cementitious materials
  • Paper and coatings
  • Hydrophobic surface treatments
  • Microporous and nanostructured carbons

The Aquadyne DVS is a fully automated, gravimetric, single or dual sample 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(s) of one or two sample(s) is/are constantly monitored and recorded as the relative humidity is automatically varied by the blending of dry carrier gas with a saturated gas stream. The dual balance design of the DVS-2 allows increased analysis throughput, side-by-side comparison with known or reference materials, or an extended mass range for a single sample. The independently temperature-controlled balance head environment ensures long term stability. The small sample chamber ensures rapid changes in sample atmosphere conditions when the relative humidity is altered during an analysis. Samples can be pre-dried in situ at up to 80degC in a flow of dry gas*. The software supports multiple users with password-controlled access.

*DVS-2HT is capable of analysis at temperatures from 10°C up to 85°C

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 sorption
  • Effect of Temperature: isotherms and kinetics change as a function of temperature. Can be used to yield sorption enthalpies

APPLICATIONS/RESULTS

  • Deliquescence: certain salts exhibit the property of dissolving in self-adsorbed water
  • Equilibrium moisture content: quantitatively the amount of water associated (adsorbed/absorbed) with the material under given atmospheric conditions of temperature and relative humidity. (Organic materials may be subject to molding according to atmospheric humidity, for example)
  • Hysteresis working range: adsorption and desorption usually differ by hysteresis - this gives a range of stability in which subsequent sorption cycles produce no change in equilibrium moisture content
  • Hydrophobicity/philicity: the shape of the isotherm reveals relative strength of affinity between water and the surface, due to polar or other chemical interactions
  • Micropore investigations: even hydrophobic materials can take up moisture if their pores are small enough
  • Crystallization phenomena: certain amorphous materials will undergo crystallization as a function of water sorption due to, for example, shifts in glass transition points
  • Sample form: sorption kinetics can be altered by the physical form of a material - powder, granule, pellet, tablet, monolith etc.

Specifications

Functional Capability Aquadyne DVS
Balance heads 1 (DVS-1)
2 (DVS-2)
Balances, type ultrasensitive electronic microbalances
Balance capacity (each) 5g
Balance capacity (combined) 10g (DVS-2 only)
Dynamic weighing range (each) -500mg to +500mg, 0 to +1000mg
Dynamic weighing range (combined) -1000mg to +1000mg
0 to +2000mg (DVS-2 only)
Weighing resolution 0.1µg
RH range <2% - 98% (depending on temperature)
RH resolution 0.1%
RH accuracy ± 0.8% RH at 25°C
Sample chamber temperature range 15-60°C (DVS-1)
<10 - 80°C (DVS-2)
Sample chamber temperature stability ± 0.1°C
Balance head temperature

Up to 75°C (DVS-1)
Up to 85°C (DVS-2)

Gas flow rates 0 - 200 cm3/min (mass flow controllers)
Viewing port / sample chamber door heated, triple-glazed
Data acquisition rate adjustable, up to 12 points per minute
Sample pan material silica
Water reservoir capacity 46 ml

 

Read more about Dynamic Water Vapor Sorption (DVS).

For more information contact us.

Gravimetric Water Sorption Analyzer - Aquadyne DVS

Aquadyne DVS-1

Water sorption analyzer sample chamber
DVS-2 sample chamber

For more information contact us.