Investigations by impedance spectroscopy on the behaviour of poly(N,N-dimethylpropargylamine) as humidity sensor

A thin film of poly(N,N-dimethylpropargylamine) (PDMPA), deposited by spin coating over a SiO2 substrate covered by an interdigitated array of chromium electrodes, was characterised by impedance spectroscopy at different relative humidity levels, ranging from ∼0 to ∼90% relative humidity (RH). The logarithm of the film conductance exhibits a linear behaviour from very low RH contents up to more than 70% RH. The dynamic range of the variation of the conductance is extremely high (∼6 orders-of-magnitude) and it allows a promising use of the film as a humidity sensor.