Nano- and microscopic surface wrinkles of linearly increasing heights prepared by periodic precipitation.

Arrays of surface wrinkles of linearly increasing heights (from tens of nanometers to tens of micrometers) were prepared via a spontaneous reaction-diffusion process based on periodic precipitation. The slopes, dimensions, and positions of the precipitation bands could be controlled precisely by adjusting the concentrations of the participating chemicals as well as the material properties of patterned substrates. Additional control of periodic precipitation by localized UV irradiation allowed for the preparation of discontinuous and curvilinear structures. The nonbinary 3D surface topographies were replicated into poly(dimethylsiloxane), and the applications of replicas in microfluidics, microseparations, and cell biology have been suggested.