Spreading Behavior of Oil on Hierarchical Microstructured PET Surfaces Fabricated Using Hot-Embossing Combined with Laser-Based Methods

In this study, the wetting behavior of microstructured polyethylene terephthalate (PET) foils for polar and nonpolar liquids produced by plate-to-plate hot embossing is investigated. For the embossing step, stainless steel plates are used as stamps, which are microstructured with single-scaled and hierarchical textures using direct laser writing and two-beam direct laser interference patterning. The imprinted microstructures, containing pillar- and line-like textures, show increased water contact angles combined with a superoleophilic behavior. Time-resolved measurements reveal that oil droplets spread rapidly on the hierarchical textures with velocities of up to 1.4 mm(2) s(-1). This functionalization of PET foils creates new opportunities for a wide range of industrial applications, such as the use of oil-based instead of solvent-based paints, an improved distribution of lubricants in mechanical components or for oil-water separation in maritime surroundings.

Automated summary

This study investigates the wetting behavior of microstructured polyethylene terephthalate (PET) foils produced by plate-to-plate hot embossing for polar and nonpolar liquids. Stainless steel plates with single-scaled and hierarchical textures created by direct laser writing and two-beam direct laser interference patterning are used as stamps for the embossing step. The imprinted microstructures, consisting of pillar- and line-like textures, exhibit increased water contact angles and superoleophilic behavior. Time-resolved measurements reveal rapid oil droplet spreading on the hierarchical textures up to velocities of 1.4 mm(2) s(-1). This functionalization of PET foils opens up new possibilities for various industrial applications such as using oil-based paints instead of solvent-based ones, improving lubricant distribution in mechanical components, or oil-water separation in maritime environments.