Tunable 3D Cone or Corn Seed Shape Nanostructure on Polydimethylsiloxane Surface with Oxygen Plasma Treatment

We report on a plasma-based method to fabricate a repeatable three-dimensional structure on polydimethylsiloxane (PDMS) surfaces. The pattern shape and its radius and height are controllable, and the shape can vary between rounded head corn seed shape and cone shape. The PDMS film has a periodic channeling pattern as the base pattern, and then the plasma treatment creates the cone shape with a specific method to impose the film to air plasma. By controlling the time and plasma power and also controlling the physical position of the film to plasma, a 3D shape pattern with a high surface area is shaped on the PDMS surface. This plasma-based procedure provides a simple, fast, and inexpensive method for creating patterned chemical functionalities on 2D and 3D PDMS surfaces for directed assembly and the development of micro-scale sensors and bio-chip devices. The film wrinkling bilayer is characterized by morphology and topography characterizing methods such as atomic force microscopy imaging and scanning electron microscopy. The roughness and the size of the film pattern have been related to the time and power of the plasma device and encountering position. The wrinkling amplitude and the phase grating were also mathematically modeled by considering the wrinkling of the oxidized layer and glassy behavior.