Mechanism of Fluorocarbon Surfactants in Anti-Fingerprint Coatings and Optimized Formula Examples

Fluorocarbon surfactant, anti-fingerprint coating, anti-fingerprint formula for stainless steel, 1630 fluorocarbon surfactant, metal anti-fingerprint coating, low surface energy coating

Metal anti-fingerprint coatings feature low surface energy interfaces to repel and resist adhesion of human sweat, grease and water stains, allowing residual fingerprints to be wiped off effortlessly. They are widely applied on substrates such as stainless steel, aluminum alloy, galvanized steel sheets, kitchen and bathroom hardware, digital device casings and elevator panels. Apart from anti-fingerprint performance, the coatings also deliver excellent corrosion resistance, smoothness, abrasion resistance and anti-tarnish properties. Fluorocarbon surfactants serve as the key functional additives to maintain the long-lasting anti-fingerprint effect of coatings.

First, oriented molecular arrangement at the interface. Fluorocarbon surfactants consist of perfluoroalkyl hydrophobic and oleophobic segments as well as polar anchoring groups. After coating and curing, fluorocarbon chains align vertically on the outermost layer of the coating and form a dense monomolecular protective film. This reduces the surface tension of coatings from the conventional 40~50 mN/m to 18~22 mN/m, a value lower than the surface tension of human grease and sweat, which physically prevents the spreading and adhesion of fingerprint grease.

Second, penetration barrier protection. The compact fluorocarbon molecular layer acts as a stable physical barrier, blocking salts, organic acids and moisture in sweat from penetrating into metal substrates. It effectively avoids oxidation, tarnish and rust spots on substrates and eliminates material corrosion caused by residual fingerprints.

Third, reduced friction coefficient. Fluorocarbon chains have extremely weak intermolecular forces, which greatly lower the surface friction coefficient and improve the smoothness of coating films. Grease and sweat are hard to stay on the surface when touched by fingers, leaving faint fingerprint marks that can be removed easily.

Fourth, crosslinking and immobilization for long-term stability. Reactive fluorocarbon surfactants can crosslink with resin systems and integrate into the three-dimensional network of coating films. They will not migrate or separate out due to wiping, friction or high temperature, so the anti-fingerprint and anti-corrosion properties remain stable for a long time without performance degradation.

Fifth, enhanced stain and chemical resistance. The coatings possess outstanding resistance to acids, alkalis, detergents and sweat corrosion. They are suitable for frequently touched metal surfaces in kitchens, bathrooms, home appliances and outdoor environments, leaving no traces after contact with daily stains and disinfectants.

For industrial formulas, reactive nonionic perfluoroalkyl fluorocarbon surfactants are preferred. They are compatible with water-based, solvent-based and UV-curable coatings, and prevent defects such as cratering, whitening and delamination. The optimal dosage ranges from 0.1% to 0.3%, featuring high efficiency at low addition levels. Excessive dosage will impair the adhesion and recoatability of coating films. In the industry, fluorocarbon surfactants are usually compounded with silicone additives to make up for the poor spreading performance of fluorocarbons, achieving balanced leveling property and smooth hand feel.

Hydroxyl acrylic resin: 46.0Isocyanate curing agent: 12.0Xylene: 20.0Butyl acetate: 14.0BCS retarder solvent: 3.01630 fluorocarbon surfactant: 0.18Polyether-modified silicone leveling agent: 0.32Abrasion-resistant matting powder: 3.5

The compounding ratio of fluorocarbon surfactant to silicone additive is 1:1.78, and the total proportion of additives accounts for 0.5%. The coating is applied by spraying with a film thickness of 8~12 μm. It can be air-dried at room temperature or baked at a low temperature of 60℃ for 30 minutes.

The finished product has superior performance: the water and oil contact angle exceeds 105°, and fingerprints can be wiped away completely. No tarnish or rust occurs after 48 hours of immersion in sweat. The anti-fingerprint effect remains intact after a thousand times of abrasion and wiping. The coating film is flat and uniform, fully retaining the original texture of metal.