An Experimental Investigation of Controlled Changes in Wettability of Laser-Treated Surfaces after Various Post Treatment Methods.

Tomáš Primus,Šimon Syrovátka,Pavel Kožmín,Jan Brajer,Pavel Zeman

doi:10.3390/ma14092228

Tomáš Primus, Šimon Syrovátka + Show 3 more

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https://doi.org/10.3390/ma14092228

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Abstract

In this paper, a quick nanosecond laser micro structuring process was employed to change the surface wettability of Ti6Al4V alloy. The same laser structuring method was used throughout, but with varying input fluence. The laser processing parameters resulted in high surface melting. After laser treatment, four post-processing methods were used, namely high vacuum, low temperature annealing, storage in a polyethylene bag, and storage in ambient air. Subsequently, the water droplet contact angle was measured over a long time period of 55 days. The results show that the sample stored in ambient air remained hydrophilic. On the other hand, the sample post-processed in a vacuum chamber behaved hydrophobically with a contact angle of approximately 150°. Other post-processing did not lead to specific wettability behavior. After wettability testing, all samples were cleaned ultrasonically in distilled water. This cleaning process led to annulation of all obtained properties through post-processing. In summary, this paper shows that it is more important to study surface chemistry than topography in terms of effects on wettability. Moreover, surface wettability can be controlled by laser structuring, post-processing, and surface cleaning.

Highlights

We present fast laser surface structuring with added post treatment methods to obtain both hydrophilic and hydrophobic states
Laser surface texturing with nanosecond laser is fast method for modification of surface topography
Both the forms were indicated on the laser textured surface, where they can play a significant role according to the specific surface properties

Summary

Introduction

Many methods can be used to change surface properties, mechanical and chemical methods, as well as physical methods [1]. All of these methods lead to changes in surface roughness and increase or decrease the free surface area, and some of them lead to changes in the surface chemistry [2]. A special method for changing the afore-listed surface properties is surface structuring. The goal of surface structuring is to improve corrosion resistance, wear resistance, biocompatibility, frictional properties, anti-icing properties, self-cleaning properties etc. Many scientists studying surface modifications begin with a surface wettability understanding which can predict surface properties [3,5]

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