Flexible Liquid Sensor Based on Rubber/Graphite Composite

Abstract

Hydrocarbon liquids such as gasoline, diesel, jet fuel, and solvents are hazardous materials derived from petroleum. These materials can diffuse the rubber network structures and cause swelling in these polymers. Rubber materials containing conductive fillers exhibit a high conductivity at the higher percolation threshold. As direct effect of solvent on the polymer, swelling in the rubber composite alters the structure of the filler network and subsequently the composite properties change significantly. This Process can be considered as a signal for solvent or hydrocarbon fuel detector system and used conductive rubber composite as a flexible sensor. In this study, the nitrile/graphite composite samples were prepared containing different amounts of graphite particles. These samples have the ability to measure electrical resistance. The electrical resistance of rubber/graphite samples decreases with increasing content of graphite particles. The increase in the electrical resistance of the specimens was measured by using conductive composite swelling in toluene solvent and it was observed that all specimens eventually became electrical insulation. Samples with concentrations of 60, 70, and 80 phr are conductive after recovery and solvent removal. While their conductivity is less than that of the virgin samples. The incremental trend of electrical resistance against the conductive composite swelling was measured in toluene solvent and it was observed that all samples were eventually converted to electrical insulation. But there is little difference between the third swelling process and the second one. This phenomenon has occurred for all three samples, which reveals a good similarity with the Mullins effect.