Supporting Information: Marine Anti-Fouling. Behavior of Lubricant-Infused Nanowrinkled. Polymeric Surfaces

Transcription

1 Supporting Information: Marine Anti-Fouling Behavior of Lubricant-Infused Nanowrinkled Polymeric Surfaces Cameron S. Ware, Truis Smith-Palmer, Sam Peppou-Chapman, Liam R. J. Scarratt, Erin M. Humphries, Daniel Balzer, Chiara Neto* C. S. Ware, T. Smith-Palmer, S. Peppou-Chapman, L. R. J. Scarratt, E. M. Humphries, D. Balzer, C. Neto School of Chemistry and University of Sydney Nano Institute The University of Sydney, NSW 2006, Australia A/Prof T Smith-Palmer Department of Chemistry, St Francis Xavier University, 2321 Notre Dame Ave, Antigonish, Nova Scotia, B2G 2W5, Canada S-1

2 Figures Figure S1 Comparison of FTIR spectra for a 30 µm thick low-density polyethylene standard (a) and our commercial 25 µm thick shrinkwrap obtained from Get Packed Packing (b). Both spectra show main peaks at 719, 1465, 2846 and 2910 cm -1. Figure S2 Schematic of fabrication of lubricant-infused wrinkled surfaces. (a) Flat Polyshrink or shrinkwrap sheet prior to coating; (b) a polymer film is applied to the shrinkable sheet by spin-coating. (c) The system is annealed at C for a few minutes, inducing wrinkles on the top coat, as shown by the overlaid scanning electron micrograph. (d) The wrinkles are infused with silicone oil. S-2

3 Figure S3 SEM and AFM micrographs of 60 nm Teflon films wrinkled on shrinkwrap after different degrees of shrinking. (a) (b) Shrinking to 65% of initial size resulted in the start of single-scale nano-wrinkles. (c) - (d) Increasing shrinking to 15% of original size still showed predominantly single-scale wrinkling. (e) (f) Further increasing shrinking to 10% of original size resulted in the onset of fold formation. Height scales refer to both AFM images in each line. Figure S4 Optical micrographs of extremely low roll off angles for water droplets on Teflon wrinkles with excess silicone oil (a) applied by dip coating at 1 mm/min, withdrawing rate S-3

4 designed to coat the roughness with excess liquid, as theoretically predicted by Bico et al; 1 (b) pipetting 100 µl of additional lubricant onto the surface. The numbers indicate the value of the roll off angle. Figure S5 Wetting ridge for 10 µl water droplet placed on an infused wrinkled Teflon surface (λ = 147 nm). (a) For dip coating at 0.2 mm/min the excess lubricant across the tops of the wrinkles is minimal, resulting in a very small wetting ridge. (b) When 100 µl of excess lubricant is applied to this surface the wetting ridge dramatically increases, the outline around the droplet represents the Young-Laplace fit obtained for shape of the droplet excluding the wetting ridge, the straight red lines indicate the base line and contact angles. S-4

5 Figure S6 Attempts to mark infused surfaces with a water-based marker (a) and waterproof permanent marker (b), compared to marking the same dry surface with a water-based marker (c), and waterproof permanent marker (d) Figure S7 (a)-(b) Water droplets remain pinned on scratched dry Teflon wrinkled surfaces. (b) Scratches can be seen through the droplets pinned on the surface. (c) Scratches applied to infused surfaces did not pin water droplets. S-5

6 Figure S8 Optical micrograph of crystal violet staining on infused P4VP wrinkles (bottom) vs Teflon wrinkles (top). The samples on the right have been infused with silicone oil. Figure S9 Scanning electron micrograph (SEM) of a curved portion of a wrinkled Teflon surface. The tops of the wrinkles in this particular area appear slightly flattened due to the manual handling of the surface during molding, but retained their superhydrophobic properties. S-6

7 Once infused, the curved substrate was still highly anti-fouling, as shown in Figure 2(f) in the main text. Figure S10 In situ images of the test plate during the marine fouling test. Images were taken underwater to ensure that the results were not influenced by removing them from the water. On this Test Plate were glued both infused Teflon wrinkles and uninfused Teflon wrinkles. It was predicted that the silicone oil could creep from the infused surfaces to the uninfused surfaces whilst underwater. The infused and uninfused surfaces here were glued in alternating fashion: the first surface in the top let hand side was infused, and the one to the right and the one below it were non-infused, and so on. S-7

8 Figure S11 In situ images of the control plate during the marine fouling test. Images were taken underwater to ensure that the results were not influenced by removing them from the water. The sample in the top left fell off whilst installing the plate to the net. This control plate acted as the real benchmark of Teflon wrinkles without any silicone oil. S-8

9 Figure S12 Underwater contact angle of silicone oil on Perspex (poly(methyl methacrylate)). S-9

10 Tables Table S1 Characteristics of Teflon wrinkles on shrinkwrap: film thickness, wavelength and height of wrinkles, as measured by ellipsometry and AFM, and static wettability of the dry wrinkles. Here degree of shrinking is percentage change from the original surface area: e.g. in 65% shrinking a sample of size 1 cm 2 is shrunk to 0.65 cm 2. Teflon Film Thickness (nm) Degree of Shrinking Wrinkle Wavelength (nm) Wrinkle Height (nm) Water contact angle in air ( ) 60 nm 65% 410 ± ± nm 85% 390 ± ± nm 90% I. 300 ± 50 II ± 500 a I. 320 ± 90 II. 730 ± 150 a nm 85% 150 ± ± a Double-scale roughness achieved, smaller wrinkles (I) on top of larger scale folds (II) Table S2 Characteristics of P4VP wrinkles on Polyshrink: thickness and wavelength as measured by ellipsometry and AFM, and wettability with water and oil P4VP Film Thickness (nm) Wrinkle wavelength (nm) a Water contact angle in air ( ) Contact angle for silicone oil in water ( ) Roll-off angle of water (before and after infusion, ) 19 I. 73 ± ± ± 6 >180 II. 438 ± I. 247 ± ± ± 8 >180 I ± I. 500 ± ± ± 2 >180 II a Double-scale roughness achieved, smaller wrinkles (I) on top of larger scale folds (II) S-10

11 Table S3 Data for standard curve of silicone oil (1.00 µm in Nile red). Added Silicone Oil (µl) Measured Silicone Oil (µl) Percentage Recovery Average percentage recovery 101 ± 13 S-11

12 Table S4 Toxicity of silicone oil to Psuedoalteromonas spp. Sample Absorbance at 600 nm (50% dilution) Control 1.1 ± 0.1 1% Silicone Oil 1.0 ± 0.1 2x100 ml of tryptic soy broth and artificial seawater (1:3) were inoculated with 100 µl of Psuedoalteromonas spp. (absorbance of at 600 nm). One sample had 1 ml of silicone oil added and both were shaken at 150 rpm for 24 hours. Samples were diluted by 50% with MilliQ water prior to measurement. References 1. Bico, J.; Thiele, U.; Quéré, D., Wetting of textured surfaces. Colloids Surf. A 2002, 206, S-12