Fabrication of controlled hierarchical wrinkle structures on polydimethylsiloxane via one-step C₄F₈ plasma treatment

We report a simple method for fabricating two-dimensional and nested hierarchical wrinkle structures on polydimethylsiloxane surfaces via one-step C₄F₈ plasma treatment that innovatively combines two approaches to monolayer wrinkle structure fabrication. The wavelengths of the two dimensions of the wrinkle structures can be controlled by plasma treatment (radio frequency (RF) power and plasma treatment time) and stretching (stretching strain and axial stretching), respectively. We also analyze the different interactions between the two dimensions of wrinkle structures with different wavelengths and explain the phenomenon using Fourier waveform superposition. The character of the two dimensions and hierarchy is obvious when the wavelengths of the two wrinkles are different. In surface wetting tests, the hierarchical wrinkle shows great hydrophobicity and keeps the stretching property under 25%. (paper)