Smooth‑textured ice‑cream free of agglomeration, crystal‑clear skincare serums, and gentle eye drops that do not sting eyes — products that stabilize mixtures of oil and water all rely on an auxiliary agent known as Tween 80, chemically named Polysorbate 80. It is not a single raw material but part of a complete functional family. The six common grades include Tween 20, Tween 40, Tween 60, Tween 65, Tween 80 and Tween 85.
Tween 80 (Polysorbate 80), full chemical name Polyoxyethylene (20) sorbitan monooleate, is a non‑ionic surfactant and emulsifier. Its chemical formula is C₆₄H₁₂₄O₂₆, CAS No.: 9005‑65‑6, with an HLB value of approximately 15. It is highly hydrophilic and specialized for oil‑in‑water (O/W) emulsification. It is one of the most widely‑used emulsifying‑dispersing reagents in biochemistry, microbiology and immunology laboratories. Cloud point: around 93 °C; phase‑separation and stratification will occur at high temperatures.
Appearance: Amber / pale‑yellow viscous oily liquid at room temperature, with a slight fatty odour and faintly bitter taste.
Solubility: Freely soluble in water and ethanol; slightly soluble in mineral oil. It turns into gel at low temperature and returns to liquid state upon heating.
As a non‑ionic surfactant with HLB ≈15, it works as an O/W‑type emulsifier, widely applied in pharmaceuticals, cosmetics, food processing and biochemical laboratories.
Transportation & Storage
‑ Keep sealed, protected from light and stored in cool shaded conditions. ‑ Prioritize storage requirements specified on reagent bottle labels.
Practical Applications of Tween 80
As a non‑ionic surfactant, Tween 80 finds broad applications in microbial culture, cell culture and industrial fermentation laboratories. Its four core functions are summarized as emulsification, solubilization, dispersion and wetting.
Dispersion: Disperse oils, pigments, bacterial cells and poorly‑soluble drug particles to keep them stably suspended in solution and prevent particle aggregation and sedimentation.
Example 1: In cosmetic liquid foundation, fine solid colour pigments would clump and precipitate without Tween 80. After addition, pigments are encapsulated and evenly dispersed for smooth, non‑cakey makeup application. Example 2: Adding Tween 80 to culture media prevents microbial cells from clumping and adhering to tube walls and ensures uniform dispersion of microorganisms.
Emulsification: Reduce interfacial tension between water and oil to facilitate mixing of water‑soluble and oil‑soluble components and form stable milky‑white emulsions of two immiscible liquids.
Example: In the manufacturing of cosmetic lotions, creams and body milks, Tween 80 improves product stability and active‑ingredient absorption.
Solubilization: Phenols, lipophilic dyes and hydrophobic drug standards are poorly soluble in water. Low‑dosage Tween 80 encapsulates hydrophobic molecules to form micelles and prepare stable aqueous working solutions.
Example: It serves as emulsifier and solubilizer for injections, ophthalmic preparations, oral liquid formulations, ointments and creams, such as Vitamin K1 injection.
Wetting: Lower liquid surface tension to facilitate uniform dispersion of hydrophobic substances and enhance spreading and penetration over solid biological surfaces.
Example: Added to washing solutions for animal cell staining to improve cell‑membrane permeability.
Important Precautions
Tween 80 contains unsaturated oleic‑acid chains. Long‑term exposure to air and light triggers oxidation that generates peroxides. Peroxides can damage living cells and induce cell apoptosis, irritate skin and cause drug deterioration. Seal and store in cool dark conditions after opening; otherwise the liquid will turn yellow and develop off‑odours.
Dosage must be validated before use. Excessively high concentrations may inhibit organism growth or damage cell membranes. High‑concentration Tween 80 dissolves cell membranes and can trigger haemolysis and cell lysis when in direct contact with living cells. It irritates eyes and respiratory tracts; protective gear is required during handling.
Intravenous administration carries sensitization risks; strict dosage limits apply for injectable formulations.
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