Sodium Lauryl Sulphate

Surfactant: SLS is a powerful surfactant, meaning it lowers the surface tension of water, helping to mix water with oils and dirt. This property makes it effective in cleaning products like shampoos, body washes, and facial cleansers.

Foaming Agent: SLS is well-known for its ability to create a rich lather, which enhances the sensory experience of products like shampoos, toothpastes, and bubble baths. Consumers often associate foam with effective cleaning.

Emulsifier: In formulations containing both oil and water, SLS can act as an emulsifier, helping to stabilize and maintain the mixture, preventing separation over time.Wetting Agent: SLS improves the wetting properties of liquids, allowing them to spread more easily over surfaces. This is useful in products like mouthwashes and skin cleansers to ensure even application.

Dispersing Agent: It helps to disperse particles evenly in a formulation, which is beneficial in products like scrubs or exfoliants to ensure uniform distribution of abrasive materials.

Detergent: Due to its strong cleaning power, SLS is often used in formulations where effective removal of dirt, oils, and other impurities is required, such as in facial cleansers and household cleaning products.

Thickening Agent: SLS can contribute to the viscosity of a product, giving it a thicker consistency. This is particularly useful in shampoos and body washes, where a gel-like texture is desirable.

 

Use at Appropriate Concentrations: SLS is a strong surfactant and can be irritating at high concentrations. For leave-on products, use very low concentrations or consider alternative, milder surfactants. In rinse-off products, concentrations typically range from 0.5% to 10%, depending on the formulation and desired foaming ability.

Combine with Milder Surfactants: To reduce potential skin irritation, consider blending SLS with milder surfactants like Cocamidopropyl Betaine. This combination can soften the harshness of SLS while maintaining good foaming and cleansing properties.

pH Consideration: SLS is stable and effective in a wide pH range, but it's best to formulate products within a pH range of 5-7 to be gentle on the skin. Check the final pH of your product and adjust if necessary to avoid irritation.

Pre-dissolve SLS in Water: SLS is typically available in powder or granular form and should be fully dissolved in water before adding other ingredients. This helps ensure uniform distribution and reduces the risk of clumping.

Avoid Overheating: When heating your formulation, be cautious not to overheat SLS, as excessive heat can cause degradation and reduce its effectiveness. Add SLS to the aqueous phase at a controlled temperature, ideally below 50°C (122°F).

Consider Skin Sensitivity: If your target audience includes individuals with sensitive skin, use SLS cautiously or explore alternatives. SLS can cause dryness or irritation, especially in products intended for frequent use or for sensitive areas like the face.

Test for Compatibility: Ensure that SLS is compatible with other ingredients in your formulation, particularly in complex systems with active ingredients or oils. Conduct stability testing to ensure the final product remains stable over time.Formulation Transparency: If formulating clear or transparent products, be aware that SLS can sometimes cause cloudiness or affect the clarity of the final product. Adjust the concentration or consider adding clarifying agents if transparency is important.

Reduce Irritation Potential: Incorporate soothing agents or moisturizers, such as aloe vera, glycerin, or panthenol, in your formulation to counterbalance the potential drying effects of SLS.

Rinse-Off Formulations: SLS is most effective and less likely to cause irritation when used in rinse-off products like shampoos, body washes, and facial cleansers. For leave-on products, consider using gentler surfactants.

Chemical Name: Sodium Lauryl Sulphate

CAS Number: 151-21-3

Molecular Formula: C₁₂H₂₅NaO₄S

Molecular Weight: 288.38 g/mol

Synonyms: Sodium dodecyl sulfate, Sodium dodecyl sulphate, SDS (when in powder form)

Appearance: White to off-white powder or needles, sometimes available as a viscous liquid.

Odour: Slight characteristic odour

Solubility: Highly soluble in water; slightly soluble in ethanol

Melting Point: 204°C (399°F) (for anhydrous form)

pH (1% Solution): 7-9 (neutral to slightly alkaline)

Critical Micelle Concentration (CMC): Approximately 0.0082 M in water

Density: 0.3 – 0.5 g/cm³ (for powder form)

Foaming Ability: High; generates abundant foam in aqueous solutions

Surface Tension: 33-43 mN/m at CMC (varies with concentration and temperature)

Hydrophilic-Lipophilic Balance (HLB): 40 (highly hydrophilic)

Decomposition: Decomposes upon heating, releasing sulfur oxides

Stability: Stable under normal conditions; hydrolyzes slowly in strong acids and bases

Toxicity: Low to moderate toxicity; may cause skin and eye irritation upon direct contact

Irritancy: Known to be a skin and eye irritant, especially in high concentrations

Ecotoxicity: Harmful to aquatic life with long-lasting effects; not readily biodegradable

Handling Precautions: Avoid inhalation of dust; use protective gloves and eye protection when handling the raw material

Primary Use: Surfactant in detergents, shampoos, toothpastes, and other personal care products

Packaging: Available in bulk as powder, granules, or as a liquid concentrate

Storage: Store in a cool, dry place, away from moisture and strong oxidizing agents; keep container tightly closed to prevent contamination