Color Micropatterning with Reconfigurable Stamps

A two-phase, reaction−diffusion (RD) system is described in which printing stamps of the same geometries produce different micropatterns when applied to different surfaces. Initial outflow of water from an agarose stamp into a dry gelatin “paper” causes redistribution of a chemical “ink” contained in the stamp. Depending on the gelatin's water absorptivity, the ink is printed at different locations and develops into different types of color patterns. The mechanism of formation of these patterns is studied using stamps with polygonal tiling surface reliefs. Scaling arguments are derived that explain formation of different pattern types for different geometrical parameters of the system.