fig3

Figure 3. Pressure sensing performance of the dual-mode sensor. (A) Schematic diagram of the piezoionic mechanism of the hydrogel; (B) Cyclic pressure/release test for ten cycles; (C) Generated potential as a function of the applied pressure; (D) On-body pulse detection by fixing the pressure sensor at the wrist; (E) Generated potential as a function of the NaCl concentration in the hydrogel under the pressure of 15 kPa; (F) Open-circuit potential change when applying periodic pressure of 15 kPa with a frequency of 20 and dropping 2.0 μL NaCl solution (10 mM) on the hydrogel containing NaCl solution (1 mM).