# Polarization-Controlled Femtosecond Laser Texturing Enables Robust Antifouling Stainless Steel Surfaces

## TL;DR

This paper shows how controlling laser polarization during processing can create stainless steel surfaces that resist bacterial adhesion.

## Contribution

The study introduces polarization-controlled femtosecond laser texturing to create antifouling surfaces with tailored LIPSS.

## Key findings

- Linear polarization creates anisotropic LIPSS that enhance antifouling performance against Escherichia coli.
- Circular polarization results in isotropic surface morphologies with similar wettability but lower antifouling efficacy.
- Antifouling performance is influenced by both surface wettability and the spatial organization of LIPSS.

## Abstract

In this work, we demonstrate precise control over laser-induced periodic surface structures (LIPSS) on stainless steel (SS) using femtosecond (fs) laser processing to suppress bacterial adhesion. We systematically compare the antifouling behavior of laser-textured surfaces with distinct pattern directionalities—linear and circular. Fs laser irradiation with linear polarization produces directional and anisotropic LIPSS, which progressively evolve into more complex hierarchical surface textures as processing conditions vary. In contrast, fs laser irradiation with circular polarization yields isotropic surface morphologies. Despite these morphological differences, the surface wettability remains nearly constant, with contact angles confined to a narrow range of 32.6–36.9°. Bacterial adhesion tests using Escherichia coli reveal that surfaces patterned with anisotropic features generated by linear polarization—particularly at an incident power of 30 mW—exhibit enhanced antifouling performance compared to isotropic counterparts. These results indicate that antifouling efficacy is governed not only by surface wettability but also by the spatial organization and anisotropy of the LIPSS. This study highlights the critical role of polarization-controlled fs laser processing in tailoring surface architectures and provides a rational strategy for designing bio-resistant metallic surfaces.