Applications of ferroelectric polymers

Note that the negative sign is conventionally present to ensure a positive Poisson s ratio. 

Measurements of lateral strains in thin films can be carried out using interferometric techniques [43]. Alternatively, methods have been developed for measuring the appropriate compliance coefficients to enable 21, 031 and 0 2 fo be calculated [41]. For PVDF, values of a again depend on the manufacturer one set of results reported values of 0.25, 0.57 and 0.45 for O21, 0 1 and 0 2 respectively [43]. 

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WangTT, Herbert JM, Glass AM (1987) The applications of ferroelectric polymers. Blackie, Glasgow... 

Lovinger, A. J., Recent developments in the structure, properties, and applications of ferroelectric polymers, Jpn. J. Appl. Phys. Suppl. 2, 24, 18 (1985). 

Wang, T. Herbert, J. and Glass, A. (1988) The Applications of Ferroelectric Polymers, Blackie, Glasgow. 

In recent years, many kinds of piezoelectric devices from organic polymer nuterials have been developed and widely used as industrial as well as medical instruments [2,14,13,131). Ibble 3 lists some typical applications of ferroelectric polymers. These applications can be grouped into sensors, medical instrumenution, robotics, optical dc-... 

As a matter of fact, the application of ferroelectric polymers in medicine and robotics has often been limited to the laboratory dcvclqrment stage, and it remains mostly confined to a restricted group of users, leading in just a few cases to an industrial production suge. 

The rest of this chapter is structured as follows. Section 5.2 gives a brief historical overview together with a description of the synthesis, structure and preparation of ferroelectric polymers. Section 5.3 defines the properties required to evaluate these materials, and includes typical values and brief accounts of the measurement methods. Section 5.4 details the applications of ferroelectric polymers, covering sound transducers, biomedical, pyroelectric and mechanical applications. Conclusions are briefly described in section 5,5. 

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