Fine tuning slip additives for industrial applications

Slip additives have been used extensively by many manufacturers to modify the surface structure of a wide range of materials.  They work by reducing friction, but without compromising the material’s other properties. The use of slip additives extends across a multitude of industries - from food packaging and textiles, dyes, and lubricants, to hygiene products such as nappies.

Erucamide (13-cis-docosenamide, C₂₂H₄₃NO) is a common fatty acid amide slip additive.  It functions well, even at low concentrations, and is stable and transparent with low toxicity. It is well known for its use in the manufacture of polymers such as polyethylene and polypropylene and has also been effective as an anti-fouling, anti-fogging, anti-viral, and scratch-resistant agent.

The solution

Using X-ray reflectivity (XRR) on beamline I07 at Diamond the team were able to perform a quantitative characterisation of the structure of the surface including determining molecular packing and layer thickness. They used a model system of erucamide layers prepared via spin-coating from non-aqueous solution on hydrophilic bare silica. 

The XRR results were combined with complementary techniques to reveal insights into the nanostructure of organised erucamide surface layers. The data showed that the surface nanostructures changed with erucamide concentration. In all cases, the tails of the erucamide molecules pointed outwards creating a hydrophobic surface.