Flexible and wearable BaTiO3/polyacrylonitrile-based piezoelectric sensor for human posture monitoring

Tactile sensors are essential components of wearable electronic devices, but there are still various problems in terms of energy supply, flexibility and skin adaptability. In this paper, we report a self-powered flexible tactile sensor (FTS) mainly composed of a BaTiO3/polyacrylonitrile/Ecoflex (BTO/PAN/Ecoflex) composite film, which can be used for dynamically monitoring human plantar pressure, posture and other physiological and motion parameters. Combining the synergistic piezoelectric properties of PAN and BTO, the output voltage/current of the BTO/PAN/Ecoflex composite film is 4.5/5.8 times that of the BTO/Ecoflex composite film, with maximum instantaneous power that can reach up to 3.375 µW. Under the action of external pressure stress, the FTS can reach a normalized voltage sensitivity and voltage linearity of 0.54 V/N and 0.98, respectively. Furthermore, a human-machine interaction test system is built, which can display the stress changes of human body monitoring parts in real time according to voltage changes and different color assignments. The developed human-machine interaction test system provides a new idea for the diagnosis of flatfoot and other medical diseases. Hence, this work proposes new FTSs that use a BTO/PAN/Ecoflex composite film with high sensitivity and great output performance, thus exhibiting immense potential application prospects in medical research, personalized recognition and human-machine interaction.