Nanotechnology for Anti-Icing Application: From Superhydrophobic Surfaces to Super-Low Ice Adhesion Surfaces
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Within the past two decades, the Arctic regions have attracted significant attentions from all over the world because of appraisals on an undiscovered wealth of petroleum and mineral resources. Harsh environmental challenges, however, prevent humans to step forward in the Arctic regions due to the inescapability of ice formation and accretion on exposed surfaces. Fortunately, with great efforts of many studies, anti-icing or icephobic surfaces (AIS) can provide an opportunity for us to explore the Arctic regions safely and efficiently. Hence, in this thesis AIS have been designed, prepared, and tested, including superhydrophobic surfaces (SHS), polymer-based surfaces with low ice adhesion, and super-low ice adhesion surfaces. The ultimate goal is to develop the state-of-the-art AIS and apply them to the Arctic regions. CuO based SHS have been prepared through the selective growth of metallic micro/nanostructures on desired surface areas in an alkaline solution. Copper micropillars or microholes were obtained by photolithography and chemically assisted ion beam etching (CAIBE), and the surface modification was achieved by changing different etching gases during a CAIBE process. The CuO microholes based SHS show a reduction of 31% for ice adhesion strength compared with that of bare copper surfaces. The correlations between ice adhesion strength and room temperature characteristics are fundamental principles for designing and developing ideal AIS. Current correlations, however, are established for surfaces with high ice adhesion strength (above 150 kPa). Here, a strong correlation between water adhesion force and low ice adhesion strength (below 60 kPa) has been proposed for the first time, which can provide room temperature indications for the design and screening of AIS with low ice adhesion for the Arctic applications. In order to achieve super-low ice adhesion (below 10 kPa), novel PDMS-based thin films have been developed and show lowest ice adhesion strength below 10 kPa. A new mechanism for ice detachment is introduced to explain why super-low ice adhesion of special PDMS thin films can be achieved. The original findings in this PhD study have been presented in two journal papers and two unpublished papers.