Suppression of secondary electron emission from polyimide materials with parallel and crossed groove structures

Polyimide materials (PI) are extensively used in aerospace applications, but exhibit a high secondary electron yield (SEY). In this research, we employed a femtosecond laser etching technique to create surface microstructures with various morphologies and structural parameters on PI materials to suppress secondary electron emission (SEE). SEM images confirmed the etching of microstructures with diverse morphologies and parameters on the PI surface, resulting in the formation of nano-scale structures. Analysis of surface elements following laser etching revealed an increase in C and N content and a decrease in O content. These findings were corroborated by EDS and XPS analyses. For parallel groove (PG), increasing transverse width was effectively countered by increasing longitudinal depth. For cross groove (CG), increasing transverse width was accompanied by an increase in longitudinal depth, leading to a reduction in SEY, though longitudinal depth had a smaller effect. Notably, the 40-60 of CG decreased the maximum SEY of PI material from 1.72 to 1.09. It can be indicated that the femtosecond laser treatment imparts unique etching characteristics to PI materials, which significantly mitigate the SEE. This research offers new insights and references for research aimed at reducing SEE in PI materials and other similar substances.