Temperature depended resistive property of fermented soybeans (Japanese natto) as a temperature sensor material

Abstract

Abstract Carbon-based temperature-sensitive materials have become recent topics of interest due to high demands of human sensing. To enable the practical use of these temperature sensing devices, high sensitivity, easy fabrication and disposal, and low cost are essential characteristics that should be considered. However, all these characteristics do not appear simultaneously in existing sensors. In this study, we propose and fabricate a sensitive temperature sensor using fermented soybeans (Japanese natto) as the sensing element. Natto is a naturally derived material with temperature-dependent resistance and low environmental load. Moreover, its fabrication and disposal costs are low. The changes in the resistance of the natto sheet are shown to be dependent on its water content, and a temperature coefficient of resistance of 1.15% °C−1 is achieved. The fabricated sensor shows an experimental temperature sensitivity of at least 0.1 °C. These results indicate the promising potential of using the natto sheet as a temperature sensing element.