Topographic processing of silicone surfaces

Silicone surfaces are known to form a nano-structured surface topography after irradiation in superposition with mechanical strain [P. Bodِ, J.-E. Sundgren, Thin Solid Films 136 (1986) 147; N. Bowder, W.T.S. Huck, K.E. Paul, G.M. Whitesides, Appl. Phys. Lett. 75 (1999) 2557; F. Katzenberg, Macromol. Mater. Eng. 286 (2001) 26.]. Uniaxially strained polydimethylsiloxane (PDMS) was exposed to argon plasma. This treatment results in highly regular surface undulations. The dimensions of the resulting surface topography were studied with dependence on the process parameters. The wavelength (horizontal structure dimension) of the undulations depends mainly on the plasma energy, whereas the amplitude (vertical structure dimension) is essentially influenced by the degree of strain during treatment. So far, minimal wavelengths of 100 nm have been achieved with amplitudes of 25 nm.