Contact charging method for the measurement of charge decay in electrostatic dissipative materials

Charge decay time of electrostatic dissipative materials is an important parameter in evaluating the capability of a material to control static electricity. The measurement of charge decay time, however, is not a simple task. Several methods exist, but too often the reproducibility and reliability of results is poor. In this work we have improved a contact charging method, based on the charging of a sample by a charged electrode, with the aim to increase the reproducibility and reliability of the technique. Attention was paid to the way of grounding, to sample dimensions, and to the monitoring of electrostatic potential of the sample. The improved method is presented together with test results for different kinds of electrostatic dissipative materials.