Optimization of charge storage in corona-charged fibrous electrets

This article deals with optimization of charge storage in corona-charged fibrous electrets by using desirability function approach in conjunction with design of experiments and response surface methodology of analysis. A set of fibrous electrets were prepared by varying the corona charging process factors namely applied voltage, charging time, and distance between electrodes in accordance with a full factorial design of experiment. The experimental data of initial surface potential and half-decay time were analyzed by using response surface methodology. The initial surface potential was found to be higher at higher applied voltage, longer duration of charging, and lower distance between electrodes. But, the half-decay time was found to be higher at lower applied voltage. Further, the half-decay time increased initially with the increase in charging time and distance between electrodes, but an increase in both the process factors beyond the optimum regions resulted in a decrease in half-decay time. As a compromise for the simultaneously achieving maximum amounts of 10.56 kV initial surface potential and 4.22 min half-decay time, the optimum charging conditions were found with 15 kV applied voltage, 29.4 min charging time, and 26.35 mm distance between electrodes. The predicted results showed close agreement with the experimental ones, which demonstrates the effectiveness of this approach for achieving higher charge storage in fibrous electrets.