# Three-Dimensionally Printed Microstructured Hydrophobic Surfaces: Morphology and Wettability

## TL;DR

This paper explores using 3D printing to create microstructured surfaces that repel water, with potential applications in self-cleaning and anti-wetting technologies.

## Contribution

The study introduces new microstructured geometries and surface treatments to enhance hydrophobicity in 3D-printed surfaces.

## Key findings

- Triangular-based prisms achieved superhydrophobic behavior with water contact angles up to 164°.
- Truncated pyramids and ellipsoidal cones improved print fidelity and increased hydrophobicity by 56%.
- Fluoropolymer-coated SiO2 nanoparticles further enhanced wettability by up to 18% on structured surfaces.

## Abstract

This work presents the design and fabrication of microstructured hydrophobic surfaces via fused filament fabrication (FFF) 3D printing with polylactic acid (PLA). Three geometric patterns—triangular-based prisms (TG), truncated pyramids (TP), and truncated ellipsoidal cones (CET)—were developed to modify the surface wettability. Morphological analysis revealed that the printer resolution limits the accurate reproduction of sharp CAD-defined features. Despite this, TG structures exhibited superhydrophobic behavior evaluated through static water contact angles (WCAs), reaching up to 164° along the structured direction and so representing a 100% increase relative to flat PLA surfaces (WCA = 82°). To improve print fidelity, TP and CET geometries with enlarged features were introduced, resulting in contact angles up to 128°, corresponding to a 56% increase in hydrophobicity. The truncated shapes enable the fabrication of the smallest features achievable via the FFF technique, while maintaining good resolution and obtaining higher contact angles. In addition, surface functionalization with fluoropolymer-coated SiO2 nanoparticles, confirmed by SEM and Raman spectroscopy, led to a further slight enhancement in wettability up to 18% on the structured surfaces. These findings highlight the potential of FFF-based microstructuring, combined with surface treatments, for tailoring the wetting properties of 3D-printed polymeric parts with promising applications in self-cleaning, de-icing, and anti-wetting surfaces.