LIQUID-CRYSTALS ON INTERDIGITAL STRUCTURES - APPLICATIONS AS CAPACITIVE CHEMICAL SENSORS

The dielectric behavior of nematic liquid crystals was studied with in terdigital capacitors. These microelectronic structures cause an order ed arrangement of the mesophase and dispersion curves are observed in the region of 10 kHz. Incorporated solvent vapors reduce the degree of order of the liquid crystalline host-phase, thus giving rise to a cha nge of the capacitance. Furthermore, the dispersion curves are shifted towards higher frequencies. These effects are related to the shape an d polarity of the guest molecules. More stable layers for the practica l use as chemical sensors can be realized by the more complex smectic side-chain polysiloxane.