What is determined with this method?

• The method allows the determination of the dynamic surface tension of liquids with the bubble pressure method.
• Air bubbles are generated on a capillary immersed in the liquid.
• The pressured required for bubble formation is measured and converted into surface tensions using the Young-Laplace equation.
• By varying the generation speed of the bubbles, the dependency of the surface tensions on the surface age (bubble lifetime) can be recorded.

Measuring range:

• Maximum pressure: 1.25 kPa
• Surface tension: 10 to 100 mN/m
• Temperature range (liquid): 0 to 100 °C
• Bubble lifetime: 10 to 30000 ms
• Min. required sample volume: 15 mL

What is evaluated with this method?

• Analysis of the mobility and the dynamic behaviour of surfactants and surfactant-like substances (charged polymers) in solution

Examples of application of the method by material

• Change in dynamic surface tension when surfactants are added to coating colours and liquids
• Checking the purity of water (surface tension = quality parameter)
• Concentration control of surfactants in solution

What insights do customers gain about your products/samples with this method?

• Determination of the presence of surfactants in solutions, their concentration and whether they are short-chain or long-chain molecules
• Calculation of diffusion and adsorption coefficients of surfactants

In which company or process area are these methods applied?

• Process: quality control
• Company: product development, research

Which problems can this method solve / recognise at the customer?

• Detecting impurities in liquids (quality control)
• Investigation of the behaviour of surfactants and surfactant-like substances in solution (interaction with other ingredients, micelle formation, etc.)