A Sensing Device Using Liquid Crystal in a Micropillar Array Supporting Structure

We present the design of a micropillar array that leads to the formation of stable and uniform liquid crystal (LC) thin films for sensing applications. Photolithography and electroplating methods were employed to fabricate the micropillar array. By using this microfabricated structure, thin films of LC (5CB: 4'-pentyl-4-cyanobiphenyl) were formed and stabilized against gravitational forces and mechanical shock. The geometric profile of the supported LC thin film was simulated by using finite element methods. Orientational ordering transitions of nematic LCs in the supported thin films were used to detect liquid- and vapor-phase analytes via changes in the intensity of light transmitted through the LCs. The LC thin films supported by these microfabricated structures were tested and found to respond to dimethyl methylphosphonate gas.