Robust and Sensitive Thermal Sensor Using the 3-Omega-Method to Measure the Concentration of Binary Mixtures

This article presents a platinum thin film sensor using the 3-omega-method to determine the concentration of binary mixtures. There is often the tradeoff between robustness and sensitivity. The presented approach tackles this tradeoff and the progress claims include: 1) The presented sensor shows high robustness against corrosion using an intermediate stainless-steel layer but has still high sensitivity using a only 3 µm thin Al 2 O 3 layer for the insulation between the stainless-steel layer and the platinum layer. 2) The structure leads to an improvement of the signal strength by a factor of 3 compared to previous publications. 3) The volumetric resolution of isopropanol in water is better than 1.5 vol.% for the entire range between 0 vol.% and 100 vol.%.