Silicone nanofilaments grown on aircraft alloys for low ice adhesion

Alexandre Laroche,Elmar Bonaccurso,Stefan Seeger,Davide Bottone

doi:10.1016/j.surfcoat.2021.126971

Alexandre Laroche, Elmar Bonaccurso + Show 2 more

Open Access

https://doi.org/10.1016/j.surfcoat.2021.126971

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Journal: Surface Technology	Publication Date: Feb 12, 2021
Citations: 15	License type: cc-by

Affiliation: Airbus (Germany), University of Zurich

Abstract

Abstract Many novel icephobic coatings have been shown to exhibit low adhesion strength to ice grown at null or low velocity. Of these, few have been shown to also exhibit low adhesion strength to ice grown by impacting high velocity supercooled water droplets. Even fewer of these have been shown to exhibit low adhesion strength to ice grown over a range of environmental conditions. Those that have shown such behavior have been held back by their susceptibility to certain bands of UV-exposure. Here, icephobic coatings made from Silicone Nanofilament (SNF) networks grown on anodic metal oxide surfaces are presented. They show low ice adhesion strength for a range of impact icing conditions and exhibit good durability against the tested conditions. Additionally, their nano-porous structure provides enhanced lubricant retention when infused with oil. The described coatings are a promising candidate for supporting hybrid ice protection systems on aircraft, thereby reducing the energy needed for anti−/de-icing.

Highlights

Aircraft surfaces are optimized for aerodynamic performance in a single-phase flow of air
It is possible to see from Fig. 1.a that the coating process was successful in introducing a Silicone Nanofilaments (SNFs) coating comprising two components: a relatively loose over-layer of long SNFs on top of a rough under-layer of short SNFs, whose very fine roughness closely follows that of the TiO2 nanotubes (Fig. S1.a-b) on which they were grown [44]
The Droplet Assisted Growth and Shaping (DAGS) coating method was selected to produce icephobic surfaces because many of its features are advantageous for aerospace coatings

Summary

Introduction

Aircraft surfaces are optimized for aerodynamic performance in a single-phase flow of air. Liquid contaminants like supercooled water droplets and solid contaminants such as dust, sand, or insects entering the airflow can have detrimental effects to the performance of aerodynamic surfaces. Water droplets in close proximity to each other form clouds at high altitude. The air temperature at high altitude is below freezing, but due to the purity of the water droplets, they remain in a liquid state unless perturbed [1,2,3]. An aircraft flying through the clouds is a sufficient perturbation to initiate a phase change of the supercooled water droplets [4]. Droplets impacting the surface of an aircraft quickly freeze, forming an ice layer which grows forwards as more and more droplets impact [5]

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