Nanostructures Replicated by Polymer Molding

This article discusses materials and techniques used to generate polymer replicas of nanostructures by molding, embossing, and printing. Nanostructures are defined as those that have lateral dimensions of less than 100 nm. The effect of spatially confining materials to these dimensions gives rise to physical, electronic, mechanical, magnetic, and optical properties, e.g., quantum behavior, superparamagnetism, depressed melting point, and increased hardness, that differ, at times significantly, from those of microstructures and macrostructures. The fabrication and characterization of nanostructures are important for applications in optics, computation, data storage, specialty materials, and biology. Most processes for producing electrically, magnetically, and optically functional devices containing nanostructures include four basic steps: 1) fabrication of a ‘‘master’’ (i.e., a substrate from which replicas are formed); 2) replication of the master; 3) transfer of the replica into a functional material (e.g., semiconductor or metal); and 4) registration of the pattern of a master (the same as or different than the one used originally) with that of the replica for multilayer structures. This article focuses on the polymers and the molding techniques useful for the second step of this process.