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1 Supplementary Inormation or Publication Large-area one-step assembly o 3-dimensional porous metal micro/nanocages by ethanol-assisted emtosecond laser irradiation or enhanced antirelection and hydrophobicity Guoqiang Li, Jiawen Li, Chenchu Zhang, Yanlei u, * Xiaohong Li, Jiaru Chu, Wenhao uang, and Dong Wu * Department o Precision Machinery and Precision Instrumentation, University o Science and Technology o China, eei 3006, China School o Science, Southwest University o Science and Technology, Mianyang 61010, China * huyl@ustc.edu.cn and dongwu@ustc.edu.cn Table o Contents 1. Detailed abrication o these 3D porous metal micro/nanocages arrays (S). Irradiating nickel surace with pulse energy lower than 0.05 mj or greater than 0.0 mj (S3) 3. The two-dimensional Fast Fourier transormation (D-FFT) analysis or the distribution o the micro/nanocages (S4-S5) 4. The angle-dependent relectance measurements (S6) 5. Calculation o the roughness actor or the micro/nanocage-like arrays (S7- S8) 6. The sel-cleaning eect o the micro/nanocages (S9) 7. The durability o the micro/nanocages (S10) S1

2 1. Detailed abrication o these 3D porous metal micro/nanocages arrays Fig. S1. Large-area abrication o porous 3 dimensional micro/nanocage-like arrays on nickel surace by one-step ethanol-assisted emtosecond laser irradiation. (a) Photograph o black nickel due to emtosecond laser-induced 3-dimensional micro/nanocage-like arrays. The black area with the size o mm can be easily achieved by scanning the laser beam across the nickel surace within tens o minutes. The processed area exhibits black because the relection o the blackened nickel is only about 7% in the wavelength range o nm. (b) The 45 o tilted SEM image o the processed area. It can be observed that large-area micro/nanocage-like structures are abricated on nickel surace. Moreover, the parallel scanning lines can be aintly observed. The step size between the adjacent scanning lines is 50 µm. (c) Magniied 45 o tilted SEM image o the porous micro/nanocage-like structure. This micro/nanocage looks like a cone. The body o the cone is covered with multiholes with size ranged rom tens to hundreds o nanometers. S

3 . Irradiating nickel surace with pulse energy lower than 0.05 mj or greater than 0.0 mj Fig. S. In the experiment, the pulse energy employed or the control o the growth o the micro/nanocage is chosen in the range rom 0.05 to 0.0 mj/pulse and the scanning speed is set as 1 mm/s. It is ound that the ormed micro/nanocage is not perect i the energy is too big (>0. mj) or too small (<0.05 mj). (a) SEM image o micro/nanostructures produced on nickel surace with pulse energy o 0.04 mj/pulse. One can see that typical columnar microstructures with spherical structures at the top are ormed. The magniied SEM image (b) shows that columnar microstructures exhibit porous, and look like "squid". In this case, the holes are small and the less. (c) SEM image o the imperect micro/nanocages which are produced at the pulse energy o 0.5 mj/pulse. It is seen that the spindly micro/nanocages are no longer upright. Most o the heads are hung. A careul observation rom the magniied SEM image (d) demonstrates that most o the round holes are broken into long cracks. This kind o micro/nanocages look like 3-dimensional skeletons. S3

4 3. The two-dimensional Fast Fourier transormation (D-FFT) analysis or the distribution o the micro/nanocages Fig. S3. The two-dimensional Fast Fourier transormation (D-FFT) analysis or the distribution o the micro/nanocages. The Two-dimensional Fast Fourier Transormation (D-FFT) analysis can express a requency domain unction in the time domain. In the case o a periodic unction, the D-FFT Fourier transorm 1, can be simpliied as F g x, y g( x, y)exp j x y F g X X xexp j xdx gy yexp j y gxf gy Y X X Y dxdy Y (1) where x, y represent the rectangular coordinates, g and are the time domain and requency domain unction, respectively. X, Y are the subscript, and g X (x), g Y (y) are the unction actorized by g(x, y), respectively. In our case, gx(x), gy(y) represent the distribution in x, y directions. The D-FFT provides an eective way to analyze the entire images and gives more representative values or the distribution o these micro/nanocages than singular value deduced rom the SEM images. ere we use D-FFT to get the requency inormation o the SEM images or deeply investigating the periodicity o the abricated structures. S4

5 (b) depicts the Fourier Transorm proile o the SEM images (a). It can be seen that the requency spectrum is distributed into ring and the radius o the ring is diuse within a small range. This illustrates that the micro/nanocages are ormed with characteristic periodic distribution in all directions. A careul observation o the D-FFT proile indicates that the ring is an irregular circle. This is caused by some inconsistent distribution o the micro/nanocages. This can be conirmed rom the magniied SEM image (c). The size and the spacing o the micro/nanocages are not equal absolutely. Anyway, the D-FFTs veriy the periodicity distribution o the micro/nanocages. S5

6 4. The angle-dependent relectance measurements Fig. S4. The angle-dependent relectance measurements or the micro/nanocages with size o 1.91±0.17 μm. The black and blue line represents the optical relectance o the micro/nanocages with the incident angle o 6 o and 1 o, respectively. S6

7 S7 5. Calculation o the roughness actor or the micro/nanocage-like arrays The roughness actor or a micro/nanocage is deined as the ratio o the lateral area to the projected area. The micro/nanocage model can be described by an equivalent cone, and the roughness actor can be expressed as L where and L is the bottom radius and generatrix o the cone. For the generatrix can be written as L, the roughness actor can be aliased as 1 The error can be expressed as The measured,, and, as shown in Table S1 Table S1. The measured,, and or the micro/nanocage arrays Pulse energy (mj) (μm) (μm) ±0.13 ±0.14 ±0.1 ±0.1 ±0.13 ±0.1 ±0.17 (μm) (μm) ±0.11 ±0.13 ±0.15 ±0.19 ±0.17 ±0.14 ±0.19 We can obtain and, as shown in Table S

8 Table S. The calculated and or the micro/nanocage arrays Pulse energy (mj) ±0.53 ±0.56 ±0.47 ±0.43 ±0.41 ±0.36 ±0.51 energy. It is indicated that the roughness actor is increased with the increase o the laser pulse S8

9 6. The sel-cleaning eect o the micro/nanocages Fig. S5. The wettability o the micro/nanocages with size o 1.91±0.17 μm or ethanol. (a) The water droplet rolls down along the almost superhydrophobic surace. (b) The dust particles and any pollutants on the superhydrophobic surace can be clearly washed out by the water droplets. S9

10 7. The durability o the micro/nanocages Fig. S6. The durability o the micro/nanocages with size o 1.91 μm in exploitation conditions. The micro/nanocages can keep their durability such as resistance to wear and mechanical loads. We load the structures surace by a weight o 00g (a) and then scrub it slightly or ive times (b). The SEM results show that the micro/nanocages structures are wellpreserved (c). The water contact angle is o, almost no change compared with the previous one (d). S10

11 eerences 1. Goodman, J. W. Introduction to Fourier optics. nd ed., Publisher: New York, NY: McGraw-ill, Series: McGraw-ill series in electrical and computer engineering; Electromagnetics. ISBN: (1995).. Ozaktas,. M.; Mendlovic, D. Fourier transorms o ractional order and their optical interpretation. Optics Communications 1993, S11