Printed pressure sensor array sheets fabricated using poly(amino acid)-based piezoelectric elements

We report on the device characteristics of a sheetlike flexible pressure sensor array consisting of poly(amino acid)-based piezoelectric elements fabricated on a plastic-film substrate by a printing technique. Poly(amino acid)-based piezoelectric elements were fabricated using poly(amino acid) as the piezoelectric material, silver paste ink as the electrodes, and polyimide sheet as the substrate. When dropping the load of 200 g from a height of 8.5 cm to the piezoelectric element, +1.7 and -1.4 V were observed owing to the displacement of the dipole moment in the poly(amino acid) film. We confirmed that pressures from 0 to 10,000 N were successfully measured from the change in the capacitance of the piezoelectric element, which underwent mechanical strain caused by the pressure application. The flexible pressure sensor element exhibited no noticeable degradation after repeated pressure tests at 10,000 N. Moreover, the spliced large-area pressure sensor sheet successfully detected human-stepping pressure and monitored positional information. (C) 2014 The Japan Society of Applied Physics