Nanoporous materials can be grown on concave or convex surfaces. The number of pores increases or decreases almost linearly with the thickness of the layer which is due to bifurcation or termination of single pores during growth. The stronger the curvature of the concave or convex surface, the more the growth rates differ from the growth rates on planar surfaces. The pores can be filled with metal or intrinsically conductive polymers to create micro-nano junctions for electronical or analytical use.
Doping front migration is a new effect which has been invented at the University of Münster and CeNTech. This effect occurs in structures composed of intrinsically conductive polymers. Based on this mechanism new electrochemical systems can be realized. These ultralow-cost systems represent a new class of smart labels. They contain analog and digital functions and are capable of displaying changing information to the human eye. Doping front migration controls integrated analog or digital displays and modifies load resistances of RFID transponders. In contrast to conventional smart labels the self-writing system is active even when no power is supplied by a reader. The device may also be used as a time–temperature integrator that monitors and reports product storage conditions. This may be very useful as a "best before" label on food products.