Deformation and buckling of a pre-stretched soft elastic film induced by spatially modulated electric fields

We study mechanical response of a uniaxially pre-stretched soft elastic film to spatially modulated electric fields. The film is adhered onto a rigid, conductive substrate, and the electric field is generated through a periodically patterned electrode over the film. Our work shows that at low applied voltages the deformation of the film follows the pattern of the electrode, allowing for the transfer of the surface morphology of the electrode onto the film surface in opposite sign. However, when the voltage reaches a threshold, the film buckles to form stripped pattern parallel to the tensile direction. This newly resulting deformation is superposed on that before onset of buckling, leading to complicated and ordered topography of the film. The phenomenon may provide a new clue for creating ordered surface structures with the aid of elastic buckling.