Micropatterned functional interfaces on elastic substrates fabricated by fixing out of plane deformations

We report on the preparation of micropatterned functional surfaces produced by inducing an out-of-plane deformation on elastic substrates and fixing these by creating a rigid oxidized top layer. Specifically, the elastic substrate used was Polydimethylsiloxane (PDMS) and the rigid layer on top was created by ozonation of this material. We evidenced that the surface pattern formed is directly dependent on the pressure applied, the mechanical properties of the elastic substrate and on the dimensions and shape of the mask employed to define the exposed and non-exposed areas. In addition to the pattern formed, another interesting aspect is related to the ozone diffusion within the material. Softer PDMS enables more efficient diffusion and produced a thicker oxidized layer in comparison to rigid PDMS. Finally, a simulation was carried out using the distribution of Von Misses stresses of a solid plate to understand the conditions in which the applied force resulted in the rupture of the rigid oxidized layer under a permanent deformation.