Related Experiment Video
Updated: Aug 6, 2026
07:57
Accurate Determination of the Equilibrium Surface Tension Values with Area Perturbation Tests
Published on: August 30, 2019
Maximum bubble pressure method: Universal surface age and transport mechanisms in surfactant solutions
Nikolay C Christov1, Krassimir D Danov, Peter A Kralchevsky
1Laboratory of Chemical Physics & Engineering, Faculty of Chemistry, University of Sofia, 1164 Sofia, Bulgaria.
Langmuir : the ACS Journal of Surfaces and Colloids
|August 23, 2006
Summary
A new method simplifies dynamic surface tension analysis using maximum bubble pressure tensiometry. This approach yields universal surface tension curves for surfactants like sodium dodecyl sulfate (SDS) and dodecyl trimethylammonium bromide (DTAB).
Area of Science:
- Physical Chemistry
- Surface Science
- Colloid Science
Background:
- The maximum bubble pressure method is widely used for studying dynamic surface tension.
- Quantitative interpretation of dynamic surface tension data, especially for surfactant solutions, can be complex.
- Understanding adsorption kinetics is crucial for various applications involving surfactants.
Purpose of the Study:
- To develop a new, simplified approach for quantitative data interpretation in maximum bubble pressure tensiometry.
- To establish a universal method for analyzing dynamic surface tension curves of surfactant solutions.
- To identify the kinetic regime of adsorption in micellar solutions.
Main Methods:
- Theoretical analysis of results for sodium dodecyl sulfate (SDS) and dodecyl trimethylammonium bromide (DTAB).
- Characterization of the tensiometer using an apparatus function A(t) and an apparatus constant.
- Development of a new equation for processing dynamic surface tension data.
Main Results:
- The apparatus function and constant were found to be independent of surfactant type and concentration.
- A simplified data interpretation is achieved when experimental results depend on surface dilatation only through the apparatus constant.
- The proposed equation provides excellent fits for dynamic surface tension data.
- The 'BC' diffusion regime was identified for the investigated micellar solutions, indicating equilibrated fast micellar processes and negligible slow micellar processes.
Conclusions:
- The developed approach simplifies the quantitative interpretation of maximum bubble pressure tensiometry data.
- This method allows for the generation of universal dynamic surface tension curves, characteristic of the solutions.
- The enhanced bubble-pressure tensiometry is a valuable tool for detailed analysis of adsorption processes in complex systems.
Related Concept Videos
01:13Excess Pressure Inside a Drop and a Bubble
The shape of a small drop of liquid can be considered spherical, neglecting the effect of gravity. This drop can further be considered as two equal hemispherical drops put together due to surface tension. The forces acting on the spherical drop are due to the pressure of the liquid inside the drop, the pressure due to air outside the drop, and the force due to the surface tension acting on the two hemispherical drops.
01:27Surface Active Agents
Surfactants, named for their behavior at interfaces, positively adsorb at the interfaces of two phases, reducing interfacial tension. Their versatility as emulsifiers, detergents, and foaming agents stems from this ability. Surfactants, often termed amphiphiles, share the property of amphipathy, with molecules having both hydrophilic and hydrophobic portions. The hydrophilic part is called the head, and the hydrophobic part, including an elongated alkyl substituent, forms the tail.Surfactants...
01:30Micelles
Micelle formation is an intricate process that hinges on the properties of amphiphilic or amphipathic molecules and the conditions of the system in which they are found. Amphiphilic molecules, which have both hydrophilic (water-attracting) and hydrophobic (water-repelling) parts, play a critical role in this process.In aqueous environments, these molecules arrange themselves such that their hydrophilic heads are turned towards the water phase, while their hydrophobic tails are oriented away...
01:25Adsorption Isotherms II
Brunauer, Emmett, and Teller (BET) introduced a theory in 1938 that modified Langmuir's assumptions to explain multilayer physical adsorption. This theory is applicable to Type II isotherms and provides a more realistic picture of adsorption processes. The BET theory assumes a uniform solid surface with localized adsorption sites, where adsorption at one site doesn't affect adsorption at neighboring sites. This theory also allows for the possibility of additional molecules being adsorbed on top...
01:24Surface Tension
Surface tension is defined as the force per unit length (γ) acting along the surface of a liquid. It arises due to strong intermolecular forces of attraction. A molecule located inside the bulk of the liquid is surrounded by other molecules and experiences equal forces in all directions. However, a molecule at the surface experiences unbalanced forces because there are more neighboring molecules below than above. This creates a net inward force that pulls surface molecules toward the interior,...
01:22Surface Tension of Fluid
Surface tension is a fundamental property of fluids, occurring at the boundary between a liquid and a gas or between two immiscible liquids. This phenomenon arises from the cohesive forces between molecules at the fluid's surface, creating an effect similar to a stretched elastic membrane. Inside each fluid, molecules are equally attracted in all directions by neighboring molecules, but surface molecules experience a net inward force, resulting in surface tension.
Surface tension varies with...
Surface tension varies with...