On formation of electret state during friction of polymers

The electret effect resulting from friction of polymers was investigated. It is argued that the electret state in nonpolar polymers can be caused by injection processes. For friction of polar polymers dipole polarization resulting from the orientation of dipole groups was shown to be of importance. Two factors, mechanical and electrostatic, were found to be responsible for the polarization during friction of polymers. A mechanism is suggested to explain the formation of the electret state in polymers during frictional interaction