How does NaCl affect CMC?
NaCl dehydrates hydrophilic group nonionic surfactants. Therefore, CMC decreases. The length of the hydrophobic block polymer micelles is not reduced.
What are the factors affecting CMC?
There are several factors affecting the CMC point of a surfactant. These include the amphiphile chain length, dissolved salts, the structure of the head group, temperature, the structure of the alkyl chain and polar additives.
What is CMC colloid?
In colloidal and surface chemistry, the critical micelle concentration (CMC) is defined as the concentration of surfactants above which micelles form and all additional surfactants added to the system will form micelles. The CMC is an important characteristic of a surfactant.
Why does salt reduce CMC?
When salt is added, CMC decreases by decreasing the repulsive action between the charged head groups of the surfactant molecules, and this mechanism works against micelle formation. adding salt ions decrease the repulsions, so micelles can form at a lower surface active agent concentration.
Why does CMC change with electrolyte concentration?
Electrolyte decreases CMC; because the ions of the salts neutralized the charge on the micelle surface thus deceasing the thickness of ionic compound around the surfactant and electrostatic repulsion between them helping in this way to micellization process (Paredes et al.
Does CMC depend on temperature?
For each surfactant, as the system temperature increases, the CMC initially decreases and then increases, owing to the smaller probability of hydrogen bond formation at higher temperatures. The onset of micellization tends to occur at higher concentrations as the temperature increases.
How do you increase critical micelle concentration?
With nonionic surfactants, increasing the length of the hydrophilic group (polyethylene oxide) causes an increase in CMC. In general, nonionic surfactants have lower CMC values than their corresponding ionic surfactants of the same alkyl chain length.
How do you reduce CMC?
As a general rule, the CMC decreases by a factor of 2 for ionics (without added salt) and by a factor of 3 for nonionics on adding one methylene group to the alkyl chain. With nonionic surfactants, increasing the length of the hydrophilic group (polyethylene oxide) causes an increase in CMC.
What is CMC powder?
CMC Powder (Carboxymethyl Cellulose) is a food additive used as a thickening, emulsifying, and anti-caking and preservative agent. CMC is used for stabilizing ice-crème & gives a smooth texture to it. In baking, it is used to improve dough quality and stabilize fat/protein emulsions.
How do you lower CMC?
How does electrolyte affect CMC?
Electrolyte decreases CMC; because the ions of the salts neutralized the charge on the micelle surface thus deceasing the thickness of ionic compound around the surfactant and electrostatic repulsion between them helping in this way to micellization process (Paredes et al. 1984).
Why does salt decrease CMC?
What is critical micelle concentration CMC and what is its significance?
The CMC (critical micelle concentration) is the concentration of a surfactant in a bulk phase, above which aggregates of surfactant molecules, so-called micelles, start to form. The CMC is an important characteristic for surfactants.
Does CMC dissolve in water?
CMC is soluble in water at any temperature. Because of its highly hygroscopic nature, CMC hydrates rapidly. Rapid hydration may cause agglomeration and lump formation when the CMC powder is introduced into water.
How do you make a CMC solution?
Add 0.5 g of powdered carboxymethylcellulose sodium to 50 mL of water, while stirring to produce a uniform dispersion. Continue the stirring until a clear solution is produced.