Metal-polymer electret

Metal Corrosion and Wear in Contact with Metal-Polymer Electrets... 

V.A. Goldade. About electrochemical mechanism of metal-polymer electrets formation. Vysokomolecul. Soedinenia, 1989, Vol. B31, No. 1, pp. 13-17. 

EAPs can be broadly divided into two categories based on their method of actuation ionic and field-activated. Further subdivision based on their actuation mechanism and the type of material involved is also possible. Ionic polymer-metal composites, ionic gels, carbon nanotubes, and conductive polymers fall under the ionic classification. Ferroelectric polymers, polymer electrets, electrostrictive polymers, and dielectric elastomers fall under the electronic classification. 

They produced high performance electrets from thin polymer films metallized so as to yield high capacitance. Both electrical and mechanical properties of these transducers have been remarkable examples of how applications of science of solids, including knowledge of electron traps, conduction processes in insulators and the viscoelastic phenomena of semicrystalline polymers, can be combined.(6) Incidentally, similar ideas have been applied to optimization of the properties of particle microphones, through assemblies of perfectly microspherical polymer carbon systems. These have shown what limits of performance... 

Fig. 3.20. A scheme for a combined polymer antirust coating. (1) metal substrate, (2) passivating layer, (3) a layer of organic metal, (4) a layer containing corrosion inhibitors, (5) electret polymer layer...

The electret state created in the polymer essentially affects its wear against metals. The dependence of mass wear rate on ESCD value is close to parabolic (Fig. 4.8). 

The presence of dispersed fillers in the polymer material in low amounts may intensify electrization, increase the residual charge and change the friction coefficient. Introduction of the filler in the electret state exerts a still stronger effect on polymer electrization on frictional interaction with metals. Depending on the direction of the field intensity vector formed by the filler particles, the field generated by triboelectrization can be attenuated or intensified. This means that the principle of the electret-triboelectrization superposition is realized [49], which can be used to regulate the parameters of frictional interactions. Thus, by the introduction of the electret filler, e.g. mechanically activated F-3 powder, it is possible to decrease the friction force (Fig. 4.9). 

Most of the electrets are in fact heterogeneous structures containing at least one polymer-metal interface. Such heterogeneous nature is typically not taken into account, and electret state is assumed to be solely a bulk phenomenon. Besides, most of the models postulate that charge transport is controlled by monoenergetic traps. Obviously, such simplifications lead to discrepancies between model predictions and experimentally obtained data. However, charge decay in nonpolar polymer-metal stmetures is usually modeled based on the following assumptions ... 

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