[Paper Review] Multiscale ultrafast laser texturing of marble for reduced surface wetting

Rocío Ariza, Miguel Álvarez-Alegría+5 more|arXiv (Cornell University)|Jul 19, 2021

Laser Material Processing Techniques52 references17 citations

TL;DR

This study demonstrates that multiscale ultrafast laser texturing of Crema-Marfil Coto marble induces long-term hydrophobicity through combined micro- and nano-roughness and progressive surface hydroxylation, achieving a stable contact angle of ~140° after 11 months. The effect arises from laser-induced topographical structuring and time-dependent chemical evolution, including hydroxyl and hydrocarbon species, resulting in durable, self-healing wettability control without compromising aesthetics.

ABSTRACT

The modification of the wetting properties of marble surfaces upon multi-scale texturing induced by ultrafast laser processing (340 fs pulse duration, 1030 nm wavelength) has been investigated with the aim of evaluating its potential for surface protection. The contact angle (CA) of a water drop placed on the surface was used to assess the wettability of the processed areas. Although the surfaces are initially hydrophilic upon laser treatment, after a few days they develop a strong hydrophobic behavior. Marble surfaces have been irradiated with different scan line separations to elucidate the relative roles of multi-scale roughness (nano- and micro-texture) and chemical changes at the surface. The time evolution of the contact angle has been then monitored up to 11 months after treatment. A short and a long-term evolution, associated to the combined effect of multi-scale roughness and the attachment of chemical species at the surface over the time, have been observed. XPS and ATR measurements are consistent with the progressive hydroxylation of the laser treated surfaces although the additional contribution of hydrocarbon adsorbates to the wettability evolution cannot be ruled-out. The robustness of the results has been tested by CA measurements after cleaning in different conditions with very positive results.

Motivation & Objective

• To investigate the long-term wettability evolution of marble surfaces after ultrafast laser processing.
• To disentangle the contributions of multiscale topography (micro- and nano-roughness) and surface chemical changes to hydrophobicity.
• To evaluate the durability and robustness of laser-induced hydrophobicity under cleaning conditions.
• To develop a non-coating, non-invasive method for protecting marble from water-based contaminants and acid attack.

Proposed method

• Ultrafast laser processing using 340 fs, 1030 nm pulses with variable scan line separations (2–30 µm) to create multiscale textures on marble.
• Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) for surface morphology and elemental composition analysis.
• X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance infrared (ATR-IR) spectroscopy to analyze surface chemical states and functional groups.
• Contact angle (CA) measurements monitored over 11 months to assess wettability evolution.
• Controlled cleaning procedures (distilled water rinsing and soapy cloth rubbing) to test durability and self-healing capacity.
• Petrographic and cathodoluminescence analysis to confirm material integrity and laser-induced structural changes.

Experimental results

Research questions

• RQ1 How does multiscale laser texturing affect the long-term wettability of marble surfaces?
• RQ2 What is the relative contribution of micro/nano-roughness versus chemical surface evolution to hydrophobicity development?
• RQ3 How do surface chemistry changes—particularly hydroxylation and hydrocarbon adsorption—contribute to the time-dependent wettability evolution?
• RQ4 How robust is the laser-induced hydrophobicity under mechanical and chemical cleaning?
• RQ5 Can the hydrophobic effect self-heal after surface disruption?

Key findings

• The contact angle increased rapidly within the first 10 days, reaching a stable value of approximately 140° after 8–11 months of aging.
• The highest initial hydrophobicity was observed at a scan separation of 20 µm, attributed to micro-roughness effects.
• The best long-term performance was achieved at 30 µm scan separation, where maximum effective surface area enhanced chemical reactivity and hydroxylation.
• XPS and ATR-IR data confirmed surface hydroxylation and increased hydrocarbon adsorption, both contributing to hydrophobicity.
• Cleaning with distilled water caused minimal CA reduction, while soapy cloth cleaning induced a significant but reversible drop, with recovery within days.
• The hydrophobic effect demonstrated self-healing and robustness, indicating durable protection against water-based contaminants.