Preparation of polythiophene LB films and their gas sensitivities by the quartz crystal microbalance

The gas sensitivity of polythiophene LB film was investigated. As polythiophene has the conjugated double bond, the potential applications to the various devices using its conducting property have been proposed. The Langmuir-Blodgett(LB) technique has been used to manipulate conducting polymers to multilayer thin films with well defined structures and ordered molecular orientations. In this study, we have synthesized the polythiophene derivatives such as poly(octyl thiophene)(POT), poly(propanoate thiophene)(PEPT) and poly(decanoate thiophene)(PEDT), and observed their behaviors at the air/water interface. For the preparation of polythiophene LB films with good quality, we have used the mixed monolayer with surface active materials like octadecylamine(ODA) and controlled the subphase conditions. Also, for the application to the sensing materials, we have tested the gas sensitivities of polythiophene derivatives LB films to NO2 gas by the quartz crystal microbalance(QCM).