Emulsions and Mr. EmulsifierEmulsions and Mr. Emulsifier

Go to Slide Show mode, click the red button and enjoy!

EmulsionsEmulsions

We will examine an oil-in-water We will examine an oil-in-water emulsionemulsion

These are common in food These are common in food systems and include things systems and include things like mayonnaiselike mayonnaise

Here is our prototypical Here is our prototypical system with two oil droplets system with two oil droplets dispersed in waterdispersed in water

Emulsions (Oil in water, O/W)Emulsions (Oil in water, O/W)

oil

oil

Oil droplets wantto coalesce--this reducessurface tension

Emulsions (Oil in water, O/W)Emulsions (Oil in water, O/W)

oil

Emulsions (Oil in water, O/W)Emulsions (Oil in water, O/W)

oil

Separates and floats to top because oilis less dense than water

Emulsions (Oil in water, O/W)Emulsions (Oil in water, O/W)

oil

oil

To prevent phaseseparation we needan emulsifier

EmulsifiersEmulsifiers

Emulsifiers have the following Emulsifiers have the following general molecular featuresgeneral molecular features

head Polar head, likes water

Non-polar tail, likes oil

Emulsions (Oil in water, O/W)Emulsions (Oil in water, O/W)

oil

oil

What happens to thispicture when we addemulsifiers?

Emulsions (Oil in water, O/W)Emulsions (Oil in water, O/W)

oil

oil

This system is stabilizeddue to a lowering ofsurface tension by the emulsifier.

Emulsions (Oil in water, O/W)Emulsions (Oil in water, O/W)

Now the water sees only the polar Now the water sees only the polar emulsifier heads (which, by the emulsifier heads (which, by the way, it likes)way, it likes)

The oil droplets can see only the The oil droplets can see only the nonpolar emulsifier tails (for all it nonpolar emulsifier tails (for all it knows it is surrounded by oil)knows it is surrounded by oil)

Everybody is happy and there is no Everybody is happy and there is no driving force for separation of the driving force for separation of the phasesphases

Emulsifier analogyEmulsifier analogy

When the Purdue basketball When the Purdue basketball teams play Indiana at teams play Indiana at Assembly Hall, the place is a Assembly Hall, the place is a sea of Crimson and Creamsea of Crimson and Cream

Like thisLike this

Emulsifier analogyEmulsifier analogy

Emulsifier analogyEmulsifier analogy

To make things as To make things as uncomfortable as possible, uncomfortable as possible, Purdue students are seated Purdue students are seated together in small, separated together in small, separated groupsgroups

Like thisLike this

Emulsifier analogyEmulsifier analogy

Emulsifier analogyEmulsifier analogy

In this set up, where are the In this set up, where are the problems likely to occur?problems likely to occur?

Can you figure it out?Can you figure it out?

Emulsifier analogyEmulsifier analogyProblem here? No.

Problem here? No.

Problem here? Yes!

Emulsifier analogyEmulsifier analogy

How can we defuse this How can we defuse this potential problem (high potential problem (high tension) at the interface tension) at the interface between the Indiana students between the Indiana students and the Purdue students?and the Purdue students?

Let’s look at the interface Let’s look at the interface more closelymore closely

Emulsifier analogyEmulsifier analogy

Emulsifier analogyEmulsifier analogy

What we need at this point is a What we need at this point is a very special personvery special person

This person got their B.A. at This person got their B.A. at Indiana and their M.S. at PurdueIndiana and their M.S. at Purdue

He likes both universities (and He likes both universities (and their basketball teams) their basketball teams) passionatelypassionately

He can’t decide who to cheer forHe can’t decide who to cheer for

Emulsifier analogyEmulsifier analogy

In fact, he is so fanatical he has In fact, he is so fanatical he has had special clothes made up had special clothes made up which he wears to the gameswhich he wears to the games

One half is Black and GoldOne half is Black and Gold One half is Crimson and CreamOne half is Crimson and Cream Are you ready?Are you ready? Here he comesHere he comes

Emulsifier analogyEmulsifier analogy

Boiler Up!

Nuts!!

Mr.Emulsifier

Emulsifier analogyEmulsifier analogy

Now the Purdue fan sees Now the Purdue fan sees another Purdue fan sitting another Purdue fan sitting next to him and the IU fan sees next to him and the IU fan sees an IU fan sitting next to himan IU fan sitting next to him

Interfacial tension loweredInterfacial tension lowered Problem solvedProblem solved Boiler Up!Boiler Up!