Vibration sensor characteristics of piezoelectric electro-active paper

The possibility of EAPap as a vibration sensor based on piezoelectricity was investigated in this article. The EAPap was fabricated by regenerating and tape casting cellulose. The sample was coated by a thin laminating film for packaging. The capacitance of EAPap was measured and compared with commercial PVDF. Relative permittivity of EAPap was 12, which was the same as commercially available PVDF. This reveals that EAPap has sensing potential similar to synthetic piezo polymer film. The simple aluminum cantilevered beam was used for the vibration testing and EAPap was attached on the beam. The original EAPap sensor without grounding and shielding is greatly affected by surrounding noise, especially power noise. The power noise dropped dramatically when the sensor was grounded and shielded. The impulsive response of EAPap provided the correct dynamic characteristics of the beam, especially the twisting mode of the beam was observed clearly even though the EAPap was attached at the center of the beam. This is because the sensing capability of EAPap is based on piezoelectricity which is bidirectional strain characteristics. EAPap sensor based on piezoelectricity provided a great potential as a vibration sensor.