Requirements, test strategies, and evaluation of anti-contamination and easy-to-clean surfaces, and new approaches for development

Abstract

The use of novel insect mitigating surfaces on leading edges of aircraft is one method to assist in preserving natural laminar conditions on selected areas such as wings or vertical stabilizers. Development of such surfaces is extremely challenging because of stringent requirements on resistance to aircraft fluids and to environmental conditions such as ultraviolet radiation, rain, and sand erosion. For assessment of insect-mitigating properties of surfaces, new laboratory methods were developed that are suitable for comparing insect contamination behavior and cleanability of surfaces. When testing surfaces while considering the influence of topography and chemistry using these methods, it was observed that superhydrophobic surfaces with a particular topography are essential to reduce contamination significantly. For these surfaces, the roughest surfaces produced the lowest contamination. This observation confirms results recently published by other authors. However, the current study shows that roughness is a disadvantage for cleanability. Easy cleanability after contamination with flies or insect hemolymph-containing liquid was only observed for smooth, hydrophobic surfaces.