Dielectric behavior of thin films of unsaturated polyester-resin/carbon nanotube semiconductor composites

Since the discovery of carbon nanotubes (CNT), numerous studies have focused on the development of materials combining CNT with polymer composites to exploit both CNT's remarkable characteristics and the complimentary properties of polymer thin films. In particular, unsaturated polyester resin (UPR) and CNT composite materials have not been studied before. Here we develop and characterize a UPR/CNT-based capacity resistor gas sensor and apply it on THF vapor. The CNT's high aspect ratio provides the composite with better electrical and mechanical performance than other realizations, such as carbon black. We identify and quantify THF in a wide range of operation frequencies, under SATP conditions, as functions of the vertical distance, sample volume and operation frequency. High sensitivity, reversibility and fast response to the dielectric vapor exposure in microliter volumes are achieved. The results are also analyzed in terms of the possible mechanisms relating to THF/sensor interactions, with good correspondence between the model and measured data.