Capacitive Based Liquid Crystal Chemical and Biological Sensors

This paper demonstrates the principle of capacitive sensing in liquid crystal (LC) based sensors with potential applications to chemical and biological systems. The theory for tracking the average molecular deformation partially disorder LC film via capacitive sensing is investigated. Three capacitance measurements are required to track the average molecular orientation as well as the degree of disorder in the LC film. Sensors´ outputs are digitized by involving capacitance to digital converter to be applied to computerized applications. Both the experimental and calculated capacitances of a selected sensor structure are presented.