Oleamidopropyl Dimethylamine (OAPDMA)

Oleamidopropyl Dimethylamine – Unsaturated Tertiary Amine Surfactant for Hair and Skin Care

Chemical Structure and Synthesis
Oleamidopropyl dimethylamine is a tertiary amine surfactant synthesized by the amidation of oleic acid (C18:1 unsaturated fatty acid) with 3-aminopropyldimethylamine. Its molecular structure can be represented as:
CH₃(CH₂)₇CH=CH–(CH₂)₇CO–NH–(CH₂)₃–N(CH₃)₂

The synthesis involves the reaction:
Oleic Acid + 3-Aminopropyldimethylamine → Oleamidopropyl Dimethylamine + H₂O
The presence of a cis-double bond in the oleic acid chain imparts fluidity and flexibility, making it particularly valuable for forming soft, spreadable emulsions and enhancing the sensory properties of cosmetic formulations.

Physicochemical Properties

• Amphiphilic – balances water and oil compatibility.

• Conditioning effect – improves softness, distribution, and adhesion of active ingredients to hair and skin.

• Emulsifying activity – reduces interfacial tension, stabilizing oil-in-water (O/W) and water-in-oil (W/O) emulsions.

• Antistatic properties – reduces static charge on hair, improving manageability.

• Flexible structure – the unsaturated C18 chain contributes to improved rheological properties and a smoother skin feel.

• Mild and skin-friendly – low irritation potential, suitable for sensitive skin.

Applications

• Hair care: Shampoos, conditioners, leave-in treatments – enhances softness, shine, and wet combability.

• Skin care: Creams, lotions, moisturizers – provides emollient and smoothing effects.

• Cleansing products: Body washes, facial cleansers – improves foam texture and skin feel.

• Emulsions: Stabilizes O/W and W/O systems, improving product stability.

• Other: Used as a corrosion inhibitor and lubricant additive in industrial applications.

Key Benefits

• Provides superior conditioning and antistatic properties.

• Improves softness, manageability, and shine of hair.

• Stabilizes emulsions and enhances product texture.

• Broad compatibility with cationic, non-ionic, and amphoteric surfactants.

• Mild and low irritation – suitable for sensitive skin.

• Unsaturated C18 chain provides flexibility and improved spreadability.

• Plant-derived oleic acid base – renewable and biodegradable.

Recommended Use
Typical usage levels range from 0.5–3% in rinse-off products and 1–5% in leave-on formulations, depending on the desired conditioning effect and emulsion stability. For optimal performance, incorporate into the oil phase with mild heating (50–60°C). Can be neutralized with acids (e.g., citric acid, lactic acid) to form cationic salts, enhancing its water dispersibility and conditioning efficacy.

Safety and Handling

• Generally recognized as safe for use in cosmetics at recommended concentrations.

• Low irritation potential; well-tolerated by skin and eyes.

• Avoid contact with strong oxidizers and acids.

• Store in a cool, dry place, away from direct sunlight.

• Use appropriate personal protective equipment (gloves, safety goggles) when handling.

Quality Assurance
Each batch is tested for amine value, purity, and conditioning performance to ensure consistent quality.