Polymeric Template Assisted Formation of Gradient Concentric Metal and Metal Oxide Rings

Gradient concentric rings of polymers, including (poly[2-methoxy- 5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and poly (methyl methacrylate) (PMMA), with unprecedented regularity were formed by repeated ``stick-slip'' motion of the contact line in a sphere-on-flat geometry. Subsequently, polymer rings served as templates to direct the formation of concentric metal and metal oxide rings. Three methods were described. The first two methods made use of either UV (i.e., on MEH-PPV) or thermal treatment (i.e., on PMMA) on metal-sputtered polymer rings, followed by ultrasonication. The last method, however, was much simple and robust, involving selective removal of metal and metal oxide and polymer (i.e., PMMA) consecutively.