Polysorbate 40, also known by its trade name Tween 40, is a non-ionic surfactant and emulsifier produced by the reaction of sorbitan (a sugar-derived compound) with palmitic acid, followed by ethoxylation with ethylene oxide.
Thanks to its excellent emulsifying, stabilizing, and solubilizing properties, it is widely used in the food, cosmetic, pharmaceutical, and personal care industries.

Chemical Structure

Chemical Name: Polyoxyethylene (20) sorbitan monopalmitate
Molecular Formula: C₆₂H₁₂₂O₂₆
Average Molecular Weight: ≈ 1311 g/mol
Chemical Type: Non-ionic surfactant
HLB Value: ≈ 15.6 (suitable for oil-in-water emulsions)
Structure Description:
- Hydrophilic segment: Polyoxyethylene chain
- Lipophilic segment: Sorbitan palmitate backbone

This amphiphilic structure enables Polysorbate 40 to interact simultaneously with both aqueous and oily phases, forming stable and homogeneous emulsions.

Physical and Chemical Properties

Property	Typical Value
Appearance	Thick, amber-yellow to semi-transparent liquid
Odor	Mild, faint odor
Solubility	Soluble in water, ethanol, and certain organic solvents
Density (at 25°C)	~1.05 g/cm³
Freezing Point	–12°C to –15°C
pH Stability	Stable under neutral pH; resistant to oxidation
Thermal Stability	Stable under normal processing temperatures
Key Features	Enhances solubility of poorly soluble substances, prevents phase separation, provides good thermal stability

Applications

1. Food Industry

Used as an emulsifier in ice cream, sauces, margarine, whipped toppings, and confectionery products
Improves texture, smoothness, and uniformity of formulations
Prevents oil-water separation and extends product shelf life

2. Cosmetics and Personal Care

Commonly used in creams, lotions, shampoos, and skincare formulations
Enhances absorption of active ingredients and stabilizes emulsions
Prevents graininess or phase separation in finished products

3. Pharmaceuticals

Functions as a surfactant and stabilizer in liquid preparations, suspensions, and injectables
Improves solubility of poorly water-soluble drugs
Helps maintain stability of temperature- or light-sensitive formulations

Advantages

Multifunctional: Suitable for use across food, cosmetic, and pharmaceutical industries
High safety profile: Approved for food and cosmetic applications (FDA & EFSA compliant)
Excellent emulsion stability: Produces consistent and homogeneous systems even under variable temperature conditions
High compatibility: Easily blends with other surfactants and additives
Improves product performance: Enhances shelf life, texture, and overall quality of formulations

Limitations

May cause mild skin or eye irritation at high concentrations
Possible allergic reactions in sensitive individuals
Decomposes under extremely high temperatures or strongly alkaline conditions

Safety and Handling

Regulatory Status: Considered safe for use in foods, cosmetics, and pharmaceuticals within permitted levels (FDA & EFSA approved).
Storage Conditions:
- Store in tightly sealed, corrosion-resistant containers
- Keep in a cool, dry place (20–30°C) away from direct sunlight
- Avoid prolonged exposure to high humidity
Personal Protection (HSE):
- Use gloves and protective eyewear during handling
- In case of eye contact, rinse immediately with plenty of water

Summary

Polysorbate 40 (Tween 40) is a high-performance, non-ionic surfactant and emulsifier designed to improve product stability, solubility, and consistency.
Its balanced hydrophilic–lipophilic structure allows for efficient emulsification of oil and water phases, making it an essential ingredient in formulations requiring stability, smooth texture, and long shelf life.
By incorporating Polysorbate 40, manufacturers can achieve enhanced processing efficiency, superior product quality, and improved consumer satisfaction.