Industrial Chemistry Questions:
What kind of molecule would a micelle be classified as?
How do you explain soap acting as a emulsifier with reference to the formation of micelles?
Hey Loki!!!
Ohhhh okay we don't usually classify micelle as a molecule, rather I would say its just a mixture. A micelle is essentially a spherical structure where the hydrophobic hydrocarbon chain from soap is adsorbed (i.e. dissolved, attached) into grease/oil through dispersion force and the negatively charged hydrophilic carboxylate head interacts with water molecules through ion-dipole forces. This is how I would define as a micelle, and I attached an image below to show you what a micelle look like. Now why is it a mixture? Because nothing is reacted, nothing is consumed and its just simply soap molecules attached onto grease.
Ok so I will kinda explain emulsification to you in numbered steps so its clearer:
1. Soap molecules are dissolved in water
2. Hydrophilic head of soap ion interacts with water molecule through ion-dipole, hydrocarbon chain interacts with and dissolves into grease through dispersion forces
3. Surfactant molecules continue to adsorb into the grease, decreasing the surface tension between grease and water
4. Ion-dipole force, being a stronger intermolecular force than dispersion force, pulls grease off the surface and this forms spherical droplets known as micelles
5. The negatively charged heads on the soap repel each other, preventing grease and dirt from joining back together and this keeps micelles dispersed throughout the solution and therefore achieving the emulsifying action