Formulating 101: Emulsifiers

What is an emulsifier?

When water and oil are mixed together and vigorously shaken, a dispersion of oil droplets in water - and vice versa - is formed. When shaking stops, the phases start to separate. However, when an emulsifier is added to the system, the droplets remain dispersed, and a stable emulsion is obtained.

An emulsifier consists of a water-loving hydrophilic head and an oil-loving hydrophobic tail. The hydrophilic head is directed to the aqueous phase and the hydrophobic tail to the oil phase (see figure 1). The emulsifier positions itself at the oil/water or air/water interface and, by reducing the surface tension, has a stabilising effect on the emulsion. 

In simple terms an emulsifier is a compound that can blend oil and water together into a homogeneous mixture.

My favourite and most used emulsifier is ECOMulse 

ECOMulse is a natural source, self-emulsifier for oil in water emulsions.   It contains no ethoxylated ingredients. This system is based on acyl lactylates, which are conditioning to both hair and skin. The anionic lactylates are produced by a reaction between the acyl group of fatty acids and lactic acid. Lactic acid and fatty acids are natural moisturizing factor (NMF) constituents that are found in the skin. The lactylates are excellent viscosity enhancers, stabilizers, and conditioners. ECOMulse™ is a complete, balanced and highly desirable emulsification system. When used in lotions and creams, it will provide a soft, conditioned, talc-like feel to skin.  Note, because this is based on anionic lactylates, it does not conform to the HLB system for non-ionic surfactants and no HLB number has been determined by the manufacturer.  EcoMulse is manufactured using raw materials that are GMO-free.

It's a naturally derived compounds that fits the needs of most of my lotions and potions!  It's fairly easy to work with.  It's also often called Natramulse or Ritamulse, depending on the manufacturer.

For cationic emulsions I use SugarMulse or one of the popular BTMS formulas available.

Although the components sound long and complicated, they're natural and not at all harmful.  You will often see a company claim that their products are 'chemical free' or 'free from chemicals'.  

EVERYTHING IS A CHEMICAL.  Anything with substance or components is a chemical.  Water is a chemical compound!  Don't trip and fall for fear mongering!

Formulating 101: HLB

One of the first things you need to learn when you formulate creams, lotions, conditioners, cosmetics, etc is something called the HLB system.

In 1949, while working as a chemist at the Atlas Powder Company, William C. (Bill) Griffin developed the HLB System. HLB stands for `Hydrophile-Lipophile Balance` and is a measure of the relative proportions of water-soluble and oil soluble components in a surfactant. For any given surfactant function, such as detergency, emulsification or wetting, there is usually an optimum HLB value. Current emulsion technology dictates that the surfactants' HLB in a system must match the HLB requirement of the insoluble materials. The HLB Calculator is an Excel Worksheet based on that system that quickly and easily allows the formulator to calculate HLB requirements for cosmetic formulations.

The HLB system is a complicated formulary that helps you determine how much of certain oils and emulsifiers you need to create a stable and ph balanced emulsion, aka: lotion.  The oil portion is called the lipophilic portion and the liquid portion is called the hydrophilic portion.

Each oil and butter had a very different makeup and requires a different percentage of emulsifier to break the surface tension that keeps an oil and liquid mixture apart and keep it combined.  So you add the values of each ingredient and do some crazy math to determine what you need to do to combine everything into the consistency you want.  You also need to take into consideration the ionic charge of your ingredients, either they are cationic (positive) or anionic (negative)!

You cannot just add some em wax to some oil and mix it in with some water and get a lotion!  No!  You need to break everything down into percentages and saturation levels so that it's a balanced solution.

I hate maths, I do, but this system has made it fun for me and I love experimenting with things to change up the emolliency and the feel of the finished product!

Later this week I'll talk more about actual emulsifiers and how they work and what they're made of.

With Glitter and Gratitude!