No abstract

Parallel nanometer-scale patterning techniques such as edge lithography, [1] nanoimprint lithography (NIL), [2][3][4] soft lithography, [5,6] and combined lithography, referred to as capillary force lithography (CFL), [7][8][9][10][11] have recently attracted considerable attention because of high resolution and high reproducibility. These techniques replicate a pattern from a master mold prefabricated on a solid substrate by conformal contact without complicated equipment, leading to the fabrication of high-resolution patterns (sub-100 nm features) over large areas with high throughput. However, the widespread application of these techniques is hindered by the fact that the master mold generally needs to be prepared by electron-beam lithography via an expensive and time-consuming process.[12]We report a novel method for creating many different complex structures from a single prepattern that is either prepared from a master mold or stamped onto a solid substrate by patterning with a poly(dimethylsiloxane) (PDMS) replica mold. We show that various metal patterns including ellipses, dots, rings, chains of dots (or rings), ribbons, and wavy lines with various feature sizes can be generated from a single pattern of isolated ellipsoidal dots by simply varying the residual polymer film thickness and the reactive ion etching (RIE) time. Such periodic structures are difficult to fabricate with other methods, and their fabrication with such methods is very time-consuming. The flexibility of generating various types of pattern shapes from a single prepattern makes this approach very attractive, and it has the significant additional advantage of low cost and high efficiency because it is free of sophisticated processing. This technique enables the fabrication of large-area periodic patterns with features of various shapes and sizes, and might enable the industrial production of nanoelectronic devices, micro-/nanoelectromechanical systems (MEMS/NEMS), biochip/sensors, and micro-/nanofluidic systems. [13][14][15][16][17] Figure 1 shows the fabrication scheme for creating patterned gold nanoarrays using patterning with a PDMS replica, known as CFL. A highly uniform gold layer (∼40 nm thick) is deposited by electron beam evaporation onto a silicon wafer coated with a ∼3 nm thick chromium adhesion layer. Different types of metal or semiconductor templates can be prepared, provided that the different target layers can be deposited onto a substrate. Such hard metal masking layers can be used repeatedly as patterned molds. A thin film of polystyrene (PS, 20000 g mol -1) is spin-coated as a residual layer onto the gold surface. When the PDMS mold is placed on the PS surface and heated above the glass transition temperature (T g ), capillary forces drive the polymer into the void space of the patterns to conform to the surface topology of the mold, resulting in a negative copy of the mold. Reactive ion etching (RIE) with a gas mixture of O 2 (40 sccm) and CF 4 (60 sccm) plasma is then performed on the PS replica at a chamber pressur...

We studied the orientation of the hexagonal columnar mesophase formed by self-organization of a perfluorinated supramolecular dendrimer containing a carboxyl (-COOH) headgroup and three perfluorinated (-CF 3) tails at surfaces modified with self-assembled monolayers (SAMs). The SAMmodified surfaces studied were composed of an Au(111) substrate modified with one of five types of SAM. The SAM molecules used all had an -SH headgroup, but different terminal groups (-CF 3, -CH3, and -OH) and different spacer chain lengths. Atomic force microscopy (AFM), transmission electron microscopy (TEM), and contact angle microscopy results revealed that the lattice parameters and structure of the perfluorinated supramolecular dendrimer are retained, but the orientation of the columns is strongly affected by the characteristics of the SAM surface. The supramolecular columns took on a planar alignment on the -CF 3 and -OH terminated SAM surfaces, but exhibited a perpendicular orientation on the -CH3 terminated SAM surface. These variations in column alignment can be attributed to the types of molecular interactions between the terminal groups of the SAM molecules and the perfluorinated core/tails of the supramolecular columns. However, the surface morphology and orientation was not affected by changing the space chain length of the SAM molecules used.

The third author's name is listed incorrectly. Instead of Randy R. Carney, it should be listed as Randy P. Carney. We apologize for any confusion this may have caused.