Capacitive Sweat Sensor Constructed by Gui Diatomaceous Earth

Sweat rate monitor is an important factor for hydration in exercise and training. However, the measurement of sweat rate is complicated and time-consumption in the conventional method by a calculation of total weight loss. Sweat sensor is a potential candidate to overcome these drawbacks, which may be possible to use in wearable applications for continuous detection. In the study, a new capacitive-type sensor constructed by Gui diatomaceous earth (GDE) is first proposed for solution volume detection in μl level on flexible substrate. Solution can easily penetrate into GDE through the top electrode with interdigital patterns. Capacitance is increased with volume of RO water, which can be explained by increases of dielectric constant and response area after water penetration. Sensitivity is about 7.2 pF/μl and application volume range is from 2 to 8 μl, which is a potential candidate for human sweating rate test in the future.