Chapter 11 Piezoelectric Sensors

By using oxidizable aromatic polymers, such as polyarylene ethers or polyarylene thioethers in sensors, it is possible to obtain sensors for ozone, nitrogen dioxide, or other strong oxidizing agents, with a high resolution and a high selectivity (1).

Oxidizable aromatic polymers are aromatic polymers which contain groups, such as sulfide bridges, amino groups, diazo groups, unsaturated bonds, alkyl groups or pendant olefinic groups, which can be oxidized by oxidizing agents. Preferred oxidizable aromatic polymers are polyarylene ethers or polyarylene thioethers.

11.1 Theoretical Aspects

11.1.1 Piezoelectric Electromechanical Equation

For a piezoelectric material, the basic electromechanical equation reads as (2–4)

(11.1)

In Eq. 11.1, is the electric displacement vector, is the stress vector and is the outer electric field. Further, the matrix quantities d and ε refer to the piezoelectric constant and the permittivity, respectively.