Title :
Ferroelectric and piezoelectric properties of β-form PVDF films crystallized under high pressures and their application to high temperature ultrasonic transducers
Author :
Ohigashi, H. ; Hattori, T. ; Watanabe, T. ; Li, Guo-Rong ; Takahashi, S. ; Hikosaka, M.
Author_Institution :
Polymer Mater. Eng., Yamagata Univ., Yonezawa, Japan
Abstract :
Summary form only given. Piezoelectric and ferroelectric properties of high-pressure-crystallized PVDF (polyvinylidene fluoride) film were evaluated, and ultrasonic transducers usable at high temperatures up to 200°C were developed. The film crystallized in the hexagonal phase showed distinctive ferroelectric properties. The poled film exhibited persistent piezoelectric activity in a temperature range extending just below the melting point, and an electromechanical coupling factor kt of 0.1-0.2. Ultrasonic transducers were fabricated using this film. These transducers have proved to be applicable for measurements of acoustical properties of materials at high temperatures above 150°
Keywords :
dielectric polarisation; ferroelectric thin films; piezoelectric thin films; piezoelectric transducers; piezoelectricity; polymer films; ultrasonic transducers; β-form PVDF; 150 degC; 200 degC; acoustical properties; electromechanical coupling factor; ferroelectric properties; film; hexagonal phase; high temperature ultrasonic transducers; high-pressure-crystallized PVDF; measurements; melting point; piezoelectric activity; piezoelectric properties; poled film; polyvinylidene fluoride; Acoustic measurements; Acoustic transducers; Crystallization; Ferroelectric films; Ferroelectric materials; Piezoelectric films; Piezoelectric transducers; Temperature distribution; Ultrasonic transducers; Ultrasonic variables measurement;
Conference_Titel :
Applications of Ferroelectrics, 1990., IEEE 7th International Symposium on
Conference_Location :
Urbana-Champaign, IL
Print_ISBN :
0-7803-0190-0
DOI :
10.1109/ISAF.1990.200352
