Title :
Bioelectrets and biopiezoelectricity
Author_Institution :
Inst. for Super Mater., ULVAC, Tsukuba, Japan
fDate :
8/1/1992 12:00:00 AM
Abstract :
Some biopolymers possess polar uniaxial orientation of molecular dipoles and show pyroelectricity and piezoelectricity. Some examples of bioelectrets are described. Shear piezoelectricity is observed for elongated films of poly-L-lactic acid (PLLA). Temperature relaxations in the complex piezoelectric constants, the elastic constant, and the permittivity are observed at the glass transition temperature, ~90°C. However, the piezoelectric constants for the crystalline phase of PLLA calculated from a spherical dispersion theory are independent of temperature. Thin layers of aromatic polyurea prepared by vacuum deposition polymerization show pyroelectricity and piezoelectricity after poling, which are stable to 200°C
Keywords :
bioelectric phenomena; elastic constants; electrets; glass transition (polymers); macromolecules; permittivity; piezoelectricity; polymer films; polymerisation; 200 C; 90 C; aromatic polyurea thin layers; bioelectrets; biopolymers; complex piezoelectric constants; crystalline phase; elastic constant; elongated films; glass transition temperature; permittivity; piezoelectricity; polar uniaxial orientation of molecular dipoles; poling; poly-L-lactic acid; pyroelectricity; spherical dispersion theory; temperature relaxation; vacuum deposition polymerization; Biological materials; Bones; Dielectric materials; Optical polymers; Piezoelectric polarization; Piezoelectricity; Polymer films; Pyroelectricity; Springs; Temperature;
Journal_Title :
Electrical Insulation, IEEE Transactions on
