Supplementary Materials
Superhydrophobic surfaces cannot reduce ice adhesion
Jing Chen,1,2 Jie Liu1,2, Min He1,2, Kaiyong Li1,2, Dapeng Cui1,2, Qiaolan Zhang1,2, Xiping
Zeng1,2, Yifan Zhang1,2, Jianjun Wang,1,a) Yanlin Song1
1Beijing
National Laboratory for Molecular Sciences (BNLMS),
Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, P. R. China
E-mail: wangj220@iccas.ac.cn.
2Graduate
University of Chinese Academy of Sciences, Beijing, 100049, P. R. China
1. Surface Fabrication and Characterization
Surface Fabrication: Micro-textured silicon surfaces composed of groove and pore arrays were
fabricated using standard photolithography and reactive ion etching processes. Superhydrophilic
and superhydrophobic samples were achieved by treating microgrooved silicon surfaces with
(groove depth, groove- and ridge width 5μm) piranha solution (1:3 w/w H2O2/H2SO4) and
(heptadecafluoro-1,1,2,2-tetradecyl)-trimethoxysilane (FAS-17, Alfa Aesar), repectively. Two
flat
silicon
surfaces
treated
by
piranha
solution
and
(heptadecafluoro-1,1,2,2-tetradecyl)-trimethoxysilane were used for comparison. An as-received
silicon surface, which was cleaned with acetone, ethanol and ultrapure water, was also used in
the experiments. Hydrophilic- and hydrophobic samples composed of pores array were prepared
by
treating
micro-structured
silicon
surfaces
(heptadecafluoro-1,1,2,2-tetradecyl)-trimethoxysilane,
with
piranha
respectively.
For
solution
hydrophilic-
and
and
hydrophobic samples the depth and width of the pores is 5μm, but in each group the distance
between two neighboring pores is 40μm, 20μm, 10μm and 5μm for a, b, c and d, respectively.
Contact Angle: The static contact angle (CA) on the samples was measured at room temperature
with a CA System (DSA100, Kruss Co. Germ.). The average CA values were obtained by
measuring at five different positions on the same sample.
Ice Adhesion Measurements：
The setup for measuring the ice adhesion consists of an XY motion stage, a force transducer
(Imada ZP-500N), a home built cooling stage, and water-filled cuvettes that were frozen onto the
test surfaces. The cooling stage can hold 3×3 array of samples. First, the tested silicon wafer
surfaces were cut into 19 mm×19 mm, and fixed on the upper surface of the cooling stage. The
cuvettes, 30 mm in height and 100 mm2 in cross-sectional area, were treated with
(heptadecafluoro-1,1,2,2-tetradecyl)-trimethoxysilane to prevent the water from leaking, and
were placed onto areas of interest of the sample surface. To ensure intimate contact with the
tested surfaces, a steel plate was put on the cuvettes. 1 mL of water was injected into each
cuvette through the holes in the steel plate. Then the cooling stage with the cuvettes atop of it
was placed in a closed box, which was purged with nitrogen gas to minimize the frost formation.
The test was carried out after the water in the cuvette was kept at -15 °C for 5h, which ensured
that water froze completely. Then we drive the probe of the force transducer into the ice columns
at a speed of 0.5 mm/s and record the peak force required to detach each ice column.
Fig. S1. A photograph of the home-built ice adhesion test system.
Fig. S2. Average ice adhesion strengths on flat silicon wafer surfaces measured at different temperatures and speeds.
Fig. S3. Average ice adhesion strengths on flat silicon wafer surfaces with different wettabilities measured at –15 °C with a probe
speed of 0.5 mm/s. Insets are the profiles of water droplets on the corresponding surfaces.