Malvern Colloid Systems Particle Size Analysis

Colloids and colloidal systems impact on virtually every aspect of life. They are important components of a range of products that are used on a daily basis by the public. Examples of colloids and colloidal technologies that are an integral part of modern life include cosmetics and toiletries, food products, pharmaceutical preparations, paints, paper, water treatment, photographic materials and agrochemicals.

Colloid science is an interdisciplinary subject combining aspects of physics, chemistry, mathematics and, in some cases, biology and a full understanding of a colloidal system requires some knowledge of each subject.

Malvern Instruments has a range of systems that are suitable for the characterization of colloidal systems, including particle size analysis and determination of colloidal and rheological stability.

Surfactants

What are Surfactants?

• Widely used as emulsifiers, cleaning agents to solubilise dirt, lubricants, aids to oil recovery and dispersion, catalysis, drug delivery and cell lysis.
• Can be categorized according to the charge present in the hydrophilic portion of the molecule (after dissociation in aqueous solution): Anionic, cationic, non-ionic and ampholytic.

Surfactants and Critical Micelle Concentration (CMC)
One of the fundamental properties of a surfactant is the ability to form micelles.
Micelles are associations of molecules that form above a certain surfactant concentration that is characteristic of that particular surfactant. This is called “Critical Micelle Concentration” (CMC) and is temperature dependant.
The CMC is the single most useful quantity for characterizing surfactants. This parameter alone captures much of the surface activity of the molecule.
The CMC is also key to the industrial use or biological activity of the surfactant.

Dynamic Light Scattering is an excellent method of determination of the CMC phase diagram, providing a simple, fast method of determining the effect of temperature on the CMC, the micelle size and conformation.

More about Dynamic Light Scattering

In this section

	What are colloids?
	Colloid stability
	Malvern's analyzers for measuring colloid stability
	Online presentations and application notes on colloid stability