[Chemistry Class Notes] Micelle Pdf for Exam

Micelles in Chemistry

The molecules of soap of sodium or potassium salts are made of long-chain carboxylic acids. The ionic-end of the salts of soap dissolves in the water of the soap solution while the carbon chain dissolves in oil which is present in the dirt of the cloth. So, the soap molecules form structures called micelles. The formula for the soaps is generally denoted by the formula which is RCOO–Na+, where R is any long-chain of the alkyl group consisting of 12 to 18 carbon atoms. 

Micelles are formed by the self-assembly of amphiphilic molecules which are present in the salt of the soap. 

Micelle Emulsion

The structures of the micelles in water contain hydrophilic end and hydrophobic end. 

Micelles are formed in an aqueous solution whereby the hydrophilic part of the soap micelle faces the outside surface means in the medium of the water and the hydrophobic end forms at the core of the micelle in water.

Different Ends of Micelle in Soap Solution 

Hydrophilic End 

Hydro means water and philic means loving. So the hydrophilic part of the micellar solution is water-loving. So, the first one in the structure of micelles in water soap solution is hydrophilic which dissolves in water and is attracted to it. Forms the outer surface in the soap micelles. 

Hydrophobic End   

Hydro means water and public means hating. So the hydrophobic part of the micellar solution is water-hating. So, the second part in the structure of the muscles in soap solution is dissolved in the chain of hydrocarbons which means it is attracted to the dirt and water repulsive in nature which means the hydrophobic tail is not soluble in water and lies along the surface of the water.

Micelles Water

There is the particular temperature that is needed for the formation of micelles in water and that temperature is called Kraft temperature which is denoted by T[_{k}] and the concentration of the system must be above a particular concentration is called critical micelle concentration. 

The cleansing action of the soap is mainly due to the formation of micelle in the soap solution where soap itself in the form of micelles that is the chain of the hydrocarbons. And that helps to clean the dirt. We know that soap is the salt of sodium or potassium with the chain of fatty acid which is represented as RCOO⁻ Na⁺ where Na is sodium stearate which is denoted by the formula CH₃(CH₂)₁₆ COO⁻ Na⁺ is the major component of the soap in the solution. 

When soap is dissolved in water it divides into two parts as COO⁻ and Na⁺ ions where the hydrophilic part of the micelle is COO⁻ the group which is present in the water whereas the Na⁺ stick to the oil molecules present in the solution.

In this process, the shape of the micelles we get is in the sphere form in which the head of the micelle is pointing outwards and the tail of the micelle pointing towards the center of the sphere this arrangement of the ions forms the micelles in the soap solution.

Soap Micelle

When greasy dirt or oil which is stuck on the dirty clothes is mixed with soap micelle, the mixed micelles in the soap solution arrange themselves into tiny clusters called micelles. The hydrophilic part of the micelles in the soap solution sticks to the water and points outwards, forming the outer surface of the micelle whereas the hydrophobic part stick to the oil and helps to extract it from the medium which helps to make the cloth clean so by this process, the cloth gets cleaned in the soap solution.

Application of Micelles

• Micelles are widely used in chromatography as a media of separation of the different types of ink mixed in the solution.

• They are helpful in many biological processes in the form of carriers such as gene delivery, diagnostic imaging, and many more.

• Micelles act as emulsifiers when surfactants are above the critical micelle concentration which makes a compound soluble to the solution which is usually insoluble.

• The micellar solution is required in the digestive system of the human body that plays an important role in the removal of complex lipids and fat-soluble vitamins which are indigestible in the human body.