We report on the use of chemical patterns to align a nematic liquid crystal (LC) in LC cells. Chemical patterns on the micro-and nanoscale, down to 50 nm in feature size, were fabricated by combining nanoimprint lithography (NIL) with subsequent reactive-ion etching (RIE), chemical modification with a fluorinated silane in the gas phase, and lift-off. Simultaneous control over both polar and azimuthal orientation of the LCs is possible by using the chemical nanopatterns as LC alignment layers. The polar orientation depends on the ratio of the homeotropic/planar surface potential areas, while the LC azimuthally orients along the direction of the silane patterns.All LC applications utilize the simple principle that LCs can easily be aligned by proper treatment of the contact surfaces. Consequently, better control over the LC alignment is one of the key aspects for the next generation of LC displays.

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A thermal system used to evaluate a high throughput 96 continuous flow polymerase chain reactor (CFPCR) array was designed, fabricated, and tested. Each polymerase chain reactor (PCR) in the array required three different temperature zones to realize denaturaiton at 90°C–94°C, renaturation at 50°C–70°C, and extension at 72°C; a total of 288 temperature zones were required for the 96 CFPCR array. In an initial configuration, 18 copper strips were used to define the 288 temperature zones. Each copper strip was controlled by a PID feedback control loop. Numerical simulations were used to understand the thermal crosstalk phenomena between the micromilled copper strips, which were tightly packed since the high throughput micro-titer plate format restricted each CFPCR to a square 8 mm on a side. The lowest achievable temperature in each renaturation zone in this complicated thermal environment was also identified. Thermal crosstalk limited the minimum renaturation temperature to 61.1°C. An infrared camera was used to investigate the temperature uniformity over a 0.25 mm thick polycarbonate sheet mounted on the thermal system. The temperature distribution was not uniform due to poor contact between the copper strips and device, warm air accumulated between the packed copper strips, and greater heat transfer around the boundaries of the device. More work is required to overcome these limitations and achieve a more uniform temperature distribution for a multi well CFPCR.