Related Experiment Video
Updated: May 24, 2026
09:34
Extraction and Characterization of Surfactants from Atmospheric Aerosols
Published on: April 21, 2017
Morphologies near cloud point in aqueous ionic surfactant: scattering and NMR studies
Sanjeev Kumar1, Arti Bhadoria, Harsha Patel
1Department of Chemistry, The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, India. drksanjeev@gmail.com
The Journal of Physical Chemistry. B
|March 2, 2012
Summary
Ionic surfactant solutions exhibit a clouding phenomenon where individual micelles transform into larger aggregates. This transition, involving a small fraction of micelles, is crucial for observing clouding in tetra-n-butylammonium dodecylsulphate (TBADS) solutions.
Area of Science:
- Colloid and Surface Science
- Physical Chemistry
- Materials Science
Background:
- Clouding phenomenon is well-established for nonionic surfactants.
- Ionic surfactant clouding is a newer area of research.
- Understanding aggregate behavior in ionic solutions is key.
Purpose of the Study:
- Investigate aggregate morphologies in ionic surfactant solutions near the cloud point (CP).
- Characterize the structural changes of tetra-n-butylammonium dodecylsulphate (TBADS) during clouding.
- Determine the micellar transformations responsible for the clouding phenomenon.
Main Methods:
- Dynamic Light Scattering (DLS) to observe aggregate size changes.
- Small Angle Neutron Scattering (SANS) to analyze micellar fractions.
- Nuclear Magnetic Resonance (NMR) spectroscopy to probe molecular dynamics and interactions.
Main Results:
- DLS revealed the coexistence of individual micelles (~5 nm) and giant aggregates (~500 nm) near the CP.
- SANS provided insights into the micellar fraction changes below and above the CP.
- NMR data showed peak broadening and splitting, confirming micellar growth and the presence of two distinct morphologies.
Conclusions:
- The clouding of TBADS solutions involves a transition from individual micelles to larger aggregates.
- A small fraction of micelle conversion is sufficient to induce the clouding phenomenon.
- Multiple techniques confirm the presence of coexisting morphologies around the cloud point.
More Related Videos
Related Concept Videos
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...
01:27Surface 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...
03:22Colloids
Children at play often make suspensions such as mixtures of mud and water, flour and water, or a suspension of solid pigments in water known as tempera paint. These suspensions are heterogeneous mixtures composed of relatively large particles that are visible to the naked eye or can be seen with a magnifying glass. They are cloudy, and the suspended particles settle out after mixing. On the other hand, a solution is a homogeneous mixture in which no settling occurs and in which the dissolved...