The spontaneous emergence of patterns at surfaces is a recurring theme in modern chemistry. Here we are concerned with patterns formed from solvent evaporation, leaving nonvolatile solute left behind. Work in this field has been dominated by the quest for definitive theoretical physical interpretation. [1][2][3][4][5][6][7] Too little attention has been given to the synthesis of patterns of high fidelity and regularity. Here we report a new method to achieve hundreds of concentric rings with definite spacing; each ring is approximately nanometers high and micrometers wide. This simple yet novel approach enables one to produce and organize surface patterns in a well-ordered gradient fashion. The key improvement over past procedures is that droplet evaporation is guided through use of a restricted geometry (Figure 1a), rather than allowing solvent evaporation from a drop sitting on a single solid surface, as in copious past work. 1-14 Tentatively, we attribute the reason for improvement to the fact that evaporation is constrained to occur at the droplet edges ( Figure 1b) rather than allowed over the entire droplet area as in the traditional approach, in which droplets evaporate from a single surface. The main point is that patterns of remarkably high fidelity and regularity result.A polymer was selected as the nonvolatile component. The selection of this polymer was motivated by the relevance of conjugated polymers to potential optoelectronic devices 15 but is not believed to be essential to the results presented below. The linear conjugated polymer, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene], end-capped with dimethyl phenyl (MEH-PPV), was dissolved in toluene at concentration 0.5 mg/mL. The MEH-PPV employed here had the molecular mass of 50-300 kg/mol. To maximize homogeneity of surface chemistry and topography, single crystals of muscovite mica (ASTM V-2 grade) were cleaved, coated with a reflective film of silver on the backside for subsequent visualization of the contact spot by optical interferometry, and glued onto a cylindrical quartz mount having a diameter of ∼1 cm. These methods are adapted from the surface forces apparatus. 16 The two mica sheets were then placed about 500 µm apart with the cylinders at right angles to one another, and a drop of MEH-PPV solution was inserted (Figure 1a). Subsequently, the two curved mica sheets were brought into contact so that they touched; at the apex the geometry was equivalent to that of a sphere-on-flat. As shown in Figure 1b, this produced a capillary-held polymer solution (capillary bridge) with a diameter of ca. 6-7 mm, depending on the amount of liquid loaded. Experiments were performed at room temperature inside a sealed chamber containing the hygroscopic chemical, phosphorus pentoxide (P 2 O 5 ). Due to the wetting characteristics of toluene, a concave capillary bridge resulted.The evaporation generally took hours to complete. Afterward, the two surfaces were separated and examined by optical microscopy in the transmission mode (OM, Olympus, B...