Span 80 is a common non-ionic surfactant and emulsifier. Its chemical name is sorbitan monooleate. It is the oil-soluble counterpart to the water-soluble Tween series of emulsifiers and is known for its ability to stabilize water-in-oil emulsions.

Chemical Structure and Properties

Span 80 is created by esterifying sorbitol (a sugar alcohol) with oleic acid (a common monounsaturated fatty acid derived from vegetable sources like olive or sunflower oil). This reaction produces a molecule with a hydrophobic (oil-loving) tail and a hydrophilic (water-loving) head, but the balance is heavily skewed towards the oil-loving side.

This balance is quantified by its HLB value (Hydrophilic-Lipophilic Balance), which ranges from 0 to 20.

• Span 80 has a low HLB value of ~4.3.

  This low number classifies it as a lipophilic (oil-soluble) emulsifier, meaning it is more soluble in oil than in water.

Primary Function: Water-in-Oil Emulsification

The key function of Span 80 is to create and stabilize water-in-oil (W/O) emulsions. In this type of emulsion, tiny droplets of water are dispersed throughout a continuous oil phase. Span 80's oil-soluble nature allows it to surround the water droplets, lowering the surface tension between the oil and water and preventing them from coalescing and separating.

Common Applications

Span 80's unique properties make it valuable across numerous industries:

• Food Industry: Used as an emulsifier (E494) in baked goods, whipped toppings, and cake icing to improve texture and volume by stabilizing the fat and water components.

  Cosmetics and Personal Care: A key ingredient in skin creams, lotions, makeup (especially foundations and mascaras), and deodorants that require a water-in-oil formulation for a richer, more emollient feel on the skin.

  Pharmaceuticals: Employed in topical ointments and creams where a W/O emulsion is desired to create a barrier on the skin or to facilitate the absorption of active ingredients.

  Industrial Applications: Used as an emulsifier in lubricants, coatings, textile finishing, and as an anti-static agent.

  Chemical Synthesis: Often acts as a surfactant in polymerization reactions (e.g., for PVC) and other processes.

Span 80 vs. Tween 80

While both are sorbitan esters, they are used for opposite purposes:

• Span 80 (HLB ~4.3): Oil-soluble. Creates Water-in-Oil (W/O) emulsions.

  Tween 80 (HLB ~15): Water-soluble. Creates Oil-in-Water (O/W) emulsions.
  They are frequently used together in complex formulations to achieve a wide range of textures and enhanced stability.

Safety

Span 80 is generally recognized as safe (GRAS) by the FDA for use in food and is approved for use in cosmetics and pharmaceuticals by relevant authorities worldwide when used within specified limits.