Carbomer 940 is a cross-linked polyacrylic acid polymer that serves as an extremely efficient rheology modifier. It is renowned for its ability to generate high viscosity and crystal-clear transparency at very low dosages. It exhibits "short-flow" rheology, meaning it creates non-drip gels that instantly stop flowing when stress is removed. It possesses a high yield value, allowing it to permanently suspend insoluble ingredients (such as beads or pigments) within a formulation. While it requires neutralization with an alkali to fully hydrate and thicken, it provides excellent bio-adhesion and imparts a smooth, cushiony feel to the skin. It is widely regarded as the gold standard for formulating clear hydroalcoholic gels and styling products.

Chemical Properties

• Chemical Type: Anionic Rheology Modifier (Cross-linked Polyacrylate)

• Solubility: Hydrophilic; swells rapidly in water. Soluble in water, alcohol, and glycols upon neutralization

• Appearance: Fine, white, fluffy powder

• Stability: Shear-sensitive (best processed with low-shear mixing); sensitive to electrolytes (salts); stable in the pH range of 5–10

• Skin Feel: Smooth, lubricious, and non-tacky

Synthesis Methods

Synthesized via free-radical precipitation polymerization of acrylic acid monomers in an organic solvent (traditionally benzene), cross-linked with allyl ethers of pentaerythritol.

Functions and Usages

• High-Efficiency Thickening: Provides high viscosity at low concentrations (typically 40,000–60,000 cPs at 0.5%)

• Suspension & Stabilization: Offers excellent yield value to suspend insoluble particles and stabilize oil-in-water (O/W) emulsions against creaming

• Formulation Advantages:

• Ideal for crystal-clear hair gels and hand sanitizers

• Creates "short" flow properties (non-stringy)

• Compatible with high levels of ethanol (up to 80%)

• Typical Usage Level: 0.2% to 1.0%, depending on the desired viscosity. Requires neutralization (e.g., with TEA, NaOH, or AMP) to achieve maximum thickening