3D-Printed Surface Architecture Enhancing Superhydrophobicity and Viscous Droplet Repellency

TL;DR

This paper presents a scalable 3D-printed surface design that significantly reduces contact time of viscous droplets, improving superhydrophobicity and droplet repellency for liquids up to 3.7 times the viscosity of water.

Contribution

It introduces a novel, controllable 3D-printed surface architecture that enhances superhydrophobicity for viscous liquids, filling a gap in existing surface design strategies.

Findings

Over threefold reduction in droplet contact time for viscous liquids

Effective for liquids with viscosities up to 3.7 mPa s

Provides a scalable fabrication method for advanced surface textures

Abstract

Macro-textured superhydrophobic surfaces can reduce droplet-substrate contact times of impacting water droplets, however, surface designs with similar performance for significantly more viscous liquids are missing, despite their importance in nature and technology such as for chemical shielding, food staining repellency, and supercooled (viscous) water droplet removal in anti-icing applications. Here, we introduce a deterministic, controllable and up-scalable method to fabricate superhydrophobic surfaces with a 3D-printed architecture, combining arrays of alternating surface protrusions and indentations. We show a more than threefold contact time reduction of impacting viscous droplets up to a fluid viscosity of 3.7mPa s, which equals 3.7 times the viscosity of water at room temperature, covering the viscosity of many chemicals and supercooled water. Based on the combined consideration of the fluid flow within and the simultaneous droplet dynamics above the texture, we recommend future pathways to rationally architecture such surfaces, all realizable with the methodology presented here.