Mechanism of Emulsifier
1. Reduce interfacial tension between the water phase and the oil phase.
2. Reduce the interfacial free energy
3. Form a rigid film layer as a mechanical barrier to prevent flocculation and coalescence globule
Visualization of Mechanism
Classification of Emulsion
1. Synthetic emulsifier:anionik,kationik,nonioni ( monomolecular film )
2. Hydrophilic colloid ( multimolecular film )
3. Particulate Film ( Rigid film )
Types of Emulsifier Synthesis
1. Anionic groups such as soap, triethanolamine stearate, sodium lauryl sulfate.
2. Cationic groups such as quaternary ammonium compounds
3. Nonionic group such as sorbitan fatty acid esters, polyoxyethilen sorbitan fatty acid esters
Calculation of Emulsion
Based on Hydrophilic and Lipophilic balance so-called HLB
1. HLB values are large (7-15), the larger hydrophilic so easily soluble in water (Crillet / Tween 80= 15)
2. HLB values are small (1-6) so that the larger lipophilic soluble in oil (Kosteran / Span 80 = 4.3)
3. Emulsifier combination of these two will form a stable emulsion HLB makes = HLB need
1. Value needed to obtain a stable emulsion.
2. Need a proper HLB value depends on the type of emulsion is about to be made.
3. Determined by experiment.
How to Calculate HLB
How much kosteran and crillet needed if we want to make emulsifier which has HLB need is 7.
Kosteran HLB 4,3 = 15 - 7 = 8 = (8/10,7) x 10 = 7,5 lt
Crillet HLB 15 = 7 - 4.3 = 2,7 = (2,7/10,7) x 10 = 2,5 lt
Make of the Emulsion
The emulsion droplets process used strirrer and High Shear Mixer
Droplet comparison of the resulting
Problems occurs when the emulsion made
1. Coalescence: Combining small and large droplets in the emulsion system, in which the emulsion layer of film rupture
2. Cracking: Separation of oil and water sections. (irrevesible)
3. Flocculation: Segregation droplet without damage to the emulsion films
4. Creaming: The process of separation of the emulsion into two parts containing one part contains more dispersed phase (reversible)
The causes of cracking on emulsion.
1. Incorrect the weighing of adjuvant
2. Incorrect the HLB need (depend on the formulation and experiment)
3. There was some particle which didn't solve neither in oil or water phase.
4. Insufficient time of mixing the formula
5. The use of electrolit as the water phase like Phospat Buffer Saline ( PBS )
6. Insufficient speed of high shear mixer
If there is some question please feel free to fill the comment....