One-step transformation of a fluoro-based polymer into a superhydrophobic polymer composite

We describe the formation of superhydrophobic surfaces by controlling the surface roughness using some simple processing methods, such as annealing at 120 degrees C, freeze-drying at -40 degrees C and composite film preparation. The root-mean-square (rms) roughness and the water contact angle values of untreated poly(3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12-heneicosaffluorododecyl acrylate) (PHFDA) film prepared on silicon substrate using spin-coating technique were about 1.35 nm and theta(A)/theta(R) = 125 degrees/103 degrees, respectively. On the other hand, the annealed film C and the freeze-dried film with only a small increase in the rms roughness and the water contact angle values were 2.05 nm and theta(A)/theta(R) = 126 degrees/111 degrees, and 2.28 nm and theta(A)/theta(R) = 130 degrees/123 degrees, respectively. However, these values for the composite film composed of PHFDA and active carbon were 2.54 nm and theta(A)/theta(R) = 165 degrees/164 degrees, respectively. This method can be applied to various surfaces as long as the composites composed of nanoparticles and polymeric materials do not cause any aggregation in spin-coating.