Hydrophobic and Anti-Icing Behavior of UV-Laser-Treated Polyester Resin-Based Gelcoats

Rafał Kozera,Mateusz Tański,Robert E Przekop,Zuzanna D Krawczyk,Bogna Sztorch,Bartłomiej Przybyszewski,Xabier Garcia-Casas,Ana Borras,Robert Barbucha,Anna Boczkowska

doi:10.3390/pr8121642

Abstract

Ice accumulation on wind turbine blades due to the impact of supercooled water droplets can be reduced by the application of surfaces with anti-icing properties. Hydrophobic surfaces are considered as a promising solution because of their water repellent behavior. In recent years, short-pulsed laser technologies have been developed as an efficient technique to modify the surface properties of materials. However, the anti-icing properties of such surfaces have not yet been validated. In this work, a hybrid modification of polyester resin-based gelcoats was adopted. Laser patterning (LP) was used to produce periodic surface structures on modified unsaturated polyester resin (UPR) substrates. One of the innovations of this research is the utilization of novel purpose-made chemical modifiers for gelcoats. The implementation of linear polymethylhydrosiloxane (PMHS) as a building block is a key improvement in terms of durability and functionality of the coating, since there is an option of introducing not only groups bonding in the polyester into one molecule, but also groups that increase hydrophobicity. The other novelty is a successfully conducted experiment combining such chemical modification with laser texturization of the surface. The influence of the laser energy, pattern shape, and spatial periods on the topographical characteristics and hydrophobicity as well as the anti-icing properties of the produced surfaces were investigated. To characterize the surface topography of the produced structures, scanning electron microscopy (SEM) and profilometer were utilized. Measurements of the wettability parameters (static contact angle and contact angle hysteresis) on the treated surfaces allowed the identification of the influence of wetting behavior and laser parameters on the investigated materials. Anti-icing properties were characterized by ice adhesion (IA) and freezing delay time (FDT) tests. It was found that hybrid modification of unsaturated polyester resin by chemical modifiers and laser treatment increased the hydrophobic and anti-icing properties of polyester gelcoats.

Highlights

In the modern world, energy sources are one of the most widely discussed topics, the debate arising from an increasing environmental awareness in society and a decreasing number of finite resources such as coal or natural gas
Three new results included in this paper confirm that chemical modifiers and laser patterning increase the hydrophobicity of polyester-based coatings
The most hydrophobic materials were achieved by combining processing type no. 2 and chemical modifiers

Summary

Introduction

Energy sources are one of the most widely discussed topics, the debate arising from an increasing environmental awareness in society and a decreasing number of finite resources such as coal or natural gas. Studies have shown that around 15% of the total electricity generated in the European Union in 2019 came from wind power plants and there are goals set to further improve the statistics [1]. Wind energy accounted for 7.5% of utility-scale electricity generation in the USA in the same year [2]. It is essential to warrant the durability, cost-efficiency, and safeness of the wind turbines and take into consideration the main setbacks in the process of their design [3]. The environment in which wind turbines operate is not the most indulgent one. It is worth mentioning that wind power plants are widely applied in rather cold Scandinavian countries, with Sweden making up 10% of the wind energy produced in the European Union [1]

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