Surfactants, emulsifiers & wetting agents

The HLB system

Hydrophile lipophile balance (HLB) is a way of measuring a substances solubility within water or oil. The HLB system was created as a tool to make it easier to use non-ionic surfactants. The HLB system enables you to assign a HLB value to a surfactant and a HLB requirement to the application for that surfactant. Properly matching these values helps develop your formulations.

The Three Step Surfactant Selection Method:

1. Determine the HLB requirement of the oil.
2. Determine the most effective surfactant chemistry.
3. Determine surfactant concentration required to achieve desired stability and or rheology. 

Emulsifiers

Surfactants are useful because they allow oil and water to mix, creating emulsions. 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. Emulsions are useful in many applications within the markets in which we operate, including in the creation of metalworking fluids as well as in oil production.

Wetting agents 

All wetting agents are surfactants, but not all surfactants are wetting agents. Wetting agents are a class of surfactants that lower the interfacial tension of a liquid. An example is water. Water has a high interfacial tension, so a drop of water tends to “bead” on a hydrophobic surface, such as plastic. A wetting agent in the water will reduce the tendency of the water to bead and reduce its contact angle. 

How far a surfactant is also a wetting agent will depend strongly on the hydrophile lipophile balance of the molecule in question. 

We have developed a ground-breaking range of wetting agents that significantly reduce the surface tension of liquids allowing effortless spreading and superior wetting. Our novel products can significantly alter the wetting ability of solids, aiding in the removal of emulsifying agents in crude oil.

Like you, we are focused on producing high performance technologies with minimised environmental impact. Our highly effective Crodasinic™ wetting agent has been approved by the US EPA Design for the Environment (DfE) eco-labeling program offering independent assurance that our chemistries are safe to the environment. We also offer a wetting agent which are biodegradable and 100% biobased.

Wetting agents are used widely across oilfield applications to change wettability, enhance performance and ultimately increase profits. The following leaflet shows the contacts angles of our surface-active agents in deionised water and various brines on low and high surface energy solids. Higher surface energy materials, such as glass, allows the media to flow or “wet out” to strengthen the bond.

Polymeric surfactants

Polymeric surfactants offer many performance advantages over conventional monomerics. They are a unique class of high-performance products that have been specially designed for stabilisation or co-stabilisation of aqueous and non-aqueous emulsions and dispersions. They are molecules featuring repeating hydrophilic and hydrophobic units. A wide variety of dispersed phase polarities can be formulated across the full range of formulation types. Polymeric surfactants are non-ionic molecules that tend to strongly adsorb at the oil-water interface and form a thick steric barrier around the dispersed phase producing formulations of high stability.

Features

• Increased shear stability
• Excellent temperature stability
• High electrolyte concentration stability
• High dispersed phase volume capability
• Superior performance at low treat rates
• Aqueous and non-aqueous based formulation capability
• Dispersed phase versatility.

Polymeric emulsifiers

The required level of polymeric emulsifier depends on the type of oil, the ionic content of the aqueous phase and the desired droplet size of the final emulsion. Start with 1% surfactant on the dispersed stage, if failing then increase to 5%. 

The surfactant is usually dissolved in the oil phase if possible, with gentle warming and agitation when appropriate. In most cases it will be necessary to produce the emulsion in a high-shear mixer/emulsifier. The disperse phase should be added slowly to the continuous phase under agitation on the mixer. 

The emulsification behaviour can be modified by the addition of other non-ionic surfactants, hence initial experiments to evaluate the benefits of using polymeric surfactants should try to minimize the level of such