Validation of a Nondestructive Measurement System for Evaluating Surface Charge Distribution of Nonwoven Electret Fabrics

Nonwoven electret fabrics significantly improve the performance of filters used in various commercial products. In this study, we employed a no-contact, high-spatial-resolution surface potential distribution measurement system to verify the accuracy of evaluation methods for the surface charge distribution of nonwoven electret fabrics. Nonwoven electret fabric samples were fabricated through corona discharging, and their surface potential distributions were measured nondestructively. Thereafter, positively and negatively charged toners were dispersed to visualize the surface charge polarity of the sample. The results obtained using two measurement methods were analyzed through pixel-based analysis and higher-order local autocorrelation (HLAC) feature extraction. The results of the pixel-based analysis aligned with the charge distribution by 70–80 %, and the HLAC feature-based analysis indicated a high correlation between the overall surface charge distribution and the gray values of the images obtained using both measurement methods. These findings indicate that the proposed surface potential measurement system can effectively evaluate the surface charge distribution of nonwoven electret fabrics.