Regensburg 2007 – scientific programme

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DF: Fachverband Dielektrische Festkörper

DF 12: Electric, Electromechanical and Optical Properties II

DF 12.2: Talk

Friday, March 30, 2007, 11:10–11:30, H11

Doped Polyurethane as Matrix Material for Pyroelectric Composites — •Markus Krause and Bernd Ploss — Fachbereich SciTec, Fachhochschule Jena, Carl-Zeiss-Promenade 2, 07745 Jena

Composites of pyroelectric ceramic particles in a polymer matrix appear attractive as materials for pyroelectric sensors, in particular because of their compatibility with the process technology for integrated circuits.

There is, however, a substantial dielectric mismatch between the high dielectric permittivity of the ferroelectric ceramic particles and the significantly lower dielectric permittivity of the polymer matrix. This mismatch limits the pyroelectric activity and it is the reason for a relative low performance of such pyroelectric composites.

In recent theoretical studies we had shown that the dielectric mismatch can be reduced substantially when a well specified electric conductivity is introduced into the matrix material. Therefore, we have investigated experimentally how the dielectric function of polyurethane can be modified by doping in solutions of alkali halides. Parameters for an optimization of polyurethane as matrix material have been identified.

By applying this optimized doping to 0-3 composites of lead zirconate-titante (PZT) particles in polyurethane an increase in the pyroelectric coefficient by a factor of twenty has been achieved.