Supporting Information

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Supporting Information Superhydrophobic Coatings: Are They Really Ice-Repellent? S.A. Kulinich a,b, S.

Du d a Department of Applied Sciences, University of Quebec, Saguenay, PQ, Canada

Canada V6T 1Z1 c Institute of Industrial Science, University of Tokyo, 4-6-1

Engineering, Tianjin University,Tianjin 00072, PR China 1.

1 Supporting Information Superhydrophobic Coatings: Are They Really Ice-Repellent? S.A. Kulinich a,b, S. Farhadi a, K. Nose c, X.W. Du d a Department of Applied Sciences, University of Quebec, Saguenay, PQ, Canada G7H 2B1 b Department of Chemistry, University of British Columbia, Vancouver, BC, Canada V6T 1Z1 c Institute of Industrial Science, University of Tokyo, Komaba, Meguro-ku, Tokyo , Japan e School of Materials Science and Engineering, Tianjin University,Tianjin 00072, PR China 1. Analysis of surface morphology Figure S1. SEM surface images of a spin-coated ZrO 2 - incorporated fluoropolymer sample A taken at different magnifications. 1

2 Figure S2. Surface images of two superhydrophobic samples taken by optical profiler. The samples were prepared via spin-coating ZrO 2 -Zonyl suspension on aluminum substrates and demonstrated low CAH values. Scan size is 59 x 45 μm 2. 2

3 2. Evaluation of Shear Stress of Ice Detachment The ice-adhesion evaluation tests were conducted on Al beams with samples spun in a centrifuge (see Fig. S). The samples attached to the beams were iced in a wind tunnel at a wind speed of 10 m/s, temperature -10 o C, water feed rate of 2.5 g/m and average droplet size of ~80 µm to prepare glaze ice of up to ~1 cm thick over the area of ~.2x.0 cm 2. This ice geometry was found to be optimal to avoid cohesion failure and provide reproducible results during deicing. Ice mass and area were carefully evaluated both after icing and deicing. To balance the beam in the centrifuge, a counter-weight was used on the other side (see Fig.S). The artificially iced samples were then spun in the centrifuge placed in a climatic chamber at -10 o C to determine the speed at which ice detachment from the sample surface occurs. At the moment of the detachment (detected with sensors embedded into the centrifuge walls), the adhesion strength of ice is assumed to be equal to the centrifugal force, F = mrω 2, where m is the ice mass, r is the beam radius and ω is the rotation speed in rad/s. The shear stress, correspondingly, was calculated as τ = F/A, where A is the deiced area. Three pieces were prepared (under same conditions) for each sample, and the results were calculated as the average of the three.

4 . Centrifugal Apparatus to Measure Shear Stress of Ice Detachment (a) 2 1 (b) Figure S. (a) Sample with coating in centrifuge set-up measuring ice adhesion: (1) sample, (2) aluminum beam, () counter-weight. (b) Sample covered with artificial glaze ice. 4

5 4. Contact Angle and Wetting Hysteresis vs. Icing/Deicing Cycles Water contact angle ( o ) Water contact angle hysteresis ( o ) Number of icing / deicing tests Figure S4. CA (open circles) and CAH (filled circles) of SA coated sample C as a function of the number of icing/deicing tests. Lines are only given as guides to the eye. Figure S5. CA (open triangles) and CAH (filled triangles) of ZrO 2 -fluoropolymer sample A as a function of the number of icing/deicing events. Lines are only given as guides to the eye. 5

6 Figure S6. CA (open squares) and CAH (filled squares) of FAS- treated etched Al sample B as a function of the number of icing/deicing events. Lines are only given as guides to the eye. 6

7 5. Surface Roughness Parameters vs. Icing/Deicing Cycles 40 (a) Sq ( nm ) (b) Ssk 15 1 Sku Number of icing / deicing tests -1 Figure S7. (a) Root-mean-square roughness S q, (b) skewness S sk (filled diamonds), and kurtosis S ku (open diamonds) of SA coated sample C as a function of icing/deicing times. Lines are only given as guides to the eye. 7

On Stability and Ice-Releasing Performance of Nanostructured Fluoro-Alkylsilane-Based Superhydrophobic Al alloy2024 Surfaces

On Stability and Ice-Releasing Performance of Nanostructured Fluoro-Alkylsilane-Based Superhydrophobic Al alloy2024 Surfaces Avestia Publishing 38 International Journal of Theoretical and Applied Nanotechnology Volume 1, Issue 1, Year 2012 Journal ISSN: 1929-1248 Article ID: 006, DOI: 10.11159/ijtan.2012.006 On Stability and