A novel resistive-type humidity sensor based on poly(p-diethynylbenzene)

Abstract

Poly(p-diethynylbenzene) (PDEB) synthesized with nickel catalyst Ni(CC○CCH)2(PPh3)2 (NiC) in dioxane–toluene mixed-solvent system at 25°C shows a rich trans structure with pendant-group (○CCH) content of about 35% having higher molecular weight and good solubility. A novel resistive-type humidity sensor based on PDEB is presented. Its humi-sensing characteristics are described and discussed. The impedance of the sensor changed from ∼ 103–107 Ω in almost the whole humidity range [∼ 15–92% relative humidity (RH)], which is low compared with sensors based on other humi-sensitive conjugate polymers, and hysteresis of no more than 3% RH was observed. The sensor prepared by Langmuir–Blodgett (LB) deposition method shows the best humidity response. An explanation of humi-sensing behavior of PDEB is attempted by taking into account the interaction between hydrogen protons and super π-conjugate orbits in PDEB. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2010–2015, 1999