Title :
Bioelectret and biopiezoelectricity
Author_Institution :
Inst. for Super Mater. ULVAC, Tsukuba, Japan
Abstract :
Some biopolymers possess polar uniaxial orientation of molecular dipoles and show pyroelectricity and piezoelectricity. Some examples of bioelectret are described. Shear piezoelectricity is observed for elongated films of poly-L-lattic acid (PLLA). The temperature relaxations in complex piezoelectric constants, elastic constant, and dielectric constant are observed at the glass transition temperature around 90°C. However, the piezoelectric constants for the crystalline phase of PLLA calculated by 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 up to 200°C
Keywords :
bioelectric phenomena; dielectric polarisation; elastic constants; electrets; glass transition (polymers); molecular biophysics; molecular orientation; permittivity; piezoelectric materials; polymer films; pyroelectricity; 200 degC; 90 degC; aromatic polyurea; bioelectret; biopiezoelectricity; biopolymers; complex piezoelectric constants; crystalline phase; dielectric constant; elastic constant; elongated films; glass transition temperature; molecular dipoles; piezoelectricity; polar uniaxial orientation; poling; poly-L-lattic acid; pyroelectricity; shear piezoelectricity; spherical dispersion theory; temperature relaxations; vacuum deposition polymerization; Biological materials; Bones; Dielectric materials; Optical polymers; Piezoelectric materials; Piezoelectric polarization; Piezoelectricity; Polymer films; Pyroelectricity; Temperature;
Conference_Titel :
Electrets, 1991. (ISE 7) Proceedings., 7th International Symposium on (Cat. No.91CH3029-6)
Conference_Location :
Berlin
Print_ISBN :
0-7803-0112-9
DOI :
10.1109/ISE.1991.167297
