In this work, we report on the application
of a newly synthesized macroporous polythiophene derivative, benzo[b]thiophene
end-capped dioctyloxy-benzene(PBObzT2), in the fabrication of a capacitive
humidity sensor. The sensorhas beenfabricated by spin-coatingpolymer solutioninthe
gapbetweenpre-deposited aluminum electrodes to form a coplanar Al/PBObzT2/Al
capacitive humidity sensor. We have also demonstrated how effectively thermal
annealing has improved the physical aspects of the active layer and sensing
properties of the sensor. The sensor’s capacitance is measured against RH
variations at different frequencies. Particularly, at an optimum annealing
temperature of 75 ◦C, the sensor exhibits high sensitivity, fast response and
low hysteresis. The hydrophobic nature of the polymer makes it highly
appropriate to be used in the humidity sensors.